A Brief Chronology of Radiation and Protection

1,800,000 BC First "reactor accident." Concentration of enriched uranium forms natural nuclear reactor at Oklo, Gabon and becomes critical; core burns for 200,000 years.

500 BC Democritus and Leucippus of Greece postulate that all matter is made of indivisible units they call "atomos." "For by convention colour exist, by convention bitter, by convention sweet, but in reality atoms and void."-- Galen quoting one of Democritus' 72 lost works.

450 BC Greek philosopher Anaxagoras states that matter cannot be created nor destroyed.

79 AD First known use of uranium. Roman artisans produce yellow colored glass in mosaic mural near Naples.

1400 AD Mysterious malady kills miners at an early age in mountains around Schneeberg (Saxony) and Joachimsthal (Jachymov) in the Sudetenland (now Czechoslovakia). Called "mountain sickness."

1669 Phosphorous discovered by Hennig Brand (Germany).

1735 Platinum discovered by Julius Scaliger (Italy).

1737 Cobalt discovered by George Brandt (Sweden).

1746 Zinc discovered by Andreas Marggraf (Germany).

1751 Nickel discovered by Axel Cronstedt (Sweden).

1766 Hydrogen discovered by Henry Cavendish (England).

1772 Nitrogen discovered by Daniel Rutherford (Scotland).

1774 Oxygen discovered by Joseph Priestly (England) and Carl Wilhelm Scheele (Sweden).

1774 Chlorine discovered by Carl Wilhelm Scheele (Sweden).

1774 Manganese discovered by Johann Gahn (Sweden).

1778 Molybdenum discovered by Carl Wilhelm Scheele (Sweden).

1782 Tellurium discovered by Franz Mueller von Reichenstein (Romania).

1783 Tungsten discovered by Fausto and Juan Jose de Elhuyar (Spain).

1784 William Morgan unknowingly produces X-rays in experiment witnessed by Ben Franklin.

1789 (Sept 24) Martin Klaproth announces his discovery of a new element, uranium.

1789 Zirconium discovered by Martin Klaproth (Germany).

1790 Strontium discovered by A. Crawford (Scotland).

1791 Titanium discovered by William Gregor (England).

1794 Yttrium discovered by Johann Gadolin (Finland).

1797 Chromium discovered by Louis Vauquelin (France).

1798 Beryllium discovered by Fredrich Woehler (Germany) and A. A. Bussy (France).

1800 William Herschel (Germany-USA) discovers a point below the frequency of red light which he terms infrared.

1801 Johann Wilhelm Ritter (Germany) discovers light beyond the violet end of the spectrum which he terms ultraviolet.

1801 Niobium discovered by Charles Hatchet (England).

1802 Tantalum discovered by Anders Ekeberg (Sweden)

1803 "Thou knowest no man can split the atom." -- John Dalton

1803 Palladium discovered by William Wollaston (England).

1803 Cerium discovered by W. von Hisinger, J. Berzelius, M. Kaproth (Sweden / Germany).

1804 Rhodium discovered by William Wollaston (England).

1804 Iodine discovered by Bernard Courtois (France).

1804 Osmium discovered by Smithson Tenant (England).

1804 Iridium discovered by S. Tenant, A.F. Fourcory, L.N. Vauquelin, and H.V. Collet-Descoltils (England / France).

1807 Sodium discovered by Sir Humphrey Davy (England).

1807 Potassium discovered by Sir Humphrey Davy (England).

1808 Magnesium discovered by Sir Humphrey Davy (England).

1808 Calcium discovered by Sir Humphrey Davy (England).

1808 Barium discovered by Sir Humphrey Davy (England).

1808 John Dalton (England) formulates the Chemical Atomic Theory which states that elements combine in fixed proportions of their masses.

1811 Amedeo Avogadro (Italy) states equal volumes of all gases contain equal number of molecules under conditions of fixed temperature and pressure.

1816 William Prout (England) postulates that all atoms are made of multiples of the hydrogen atom. His work, although published anonymously, becomes known as "Prout's Hypothesis."

1817 Lithium discovered by Johann Arfvedson (Sweden).

1817 Selenium discovered by Jons Berzelius (Sweden).

1817 Cadmium discovered by Fredrich Stromeyer (Germany).

1823 Silicon discovered by Jons Berzelius (Sweden).

1824 Uranium described in Gmelin's Handbook. Much animal toxicity studies done thereafter.

1825 Aluminum discovered by Hans Christian Oersted (Denmark).

1825 Oersted observes that some undefinable magnetic effect is associated with charged particles in motion.

1826 Bromine discovered by Antoine J. Balard (France).

1828 Boron discovered by H. Day (England), J.L. Gay-Lussac and L.J. Thenard (France.)

1828 Thorium discovered by Jons Berzelius (Sweden).

1830 Vanadium discovered by Nils Stefstrom (Sweden).

1830 Michael Faraday (England) claims that moving charges (current) may be generated by moving magnetic fields.

1839 M. Daguerre discovers photography which later becomes the basis for personnel dosimetry and discovery of radioactivity in uranium.

1839 Lanthanum discovered by Carl Mosander (Sweden).

1843 Terbium discovered by Carl Mosander (Sweden).

1843 Erbium discovered by Carl Mosander (Sweden).

1844 Ruthenium discovered by Karl Klaus (Russia).

1845 (Mar 27) Wilhelm Roentgen is born.

1847 (Feb 11) Thomas Alva Edison is born.

1847 H. von Helmholz states that energy may be converted to other forms but may not be destroyed or lost.

1850 First commercial use of uranium in glass by Lloyd & Summerfield of Birmingham, England.

1852 (Dec 15) Henri Becquerel is born.

1856 Joseph John Thomson, first person to identify the existence of subatomic particles, born.

1859 Bunsen and Kirchhoff originate spectroscopy.

1860 Uranium is first used in homeopathic medicine for treatment of diabetes.

1860 Cesium discovered by Gustov Kirchhoff and Robert Bunsen (Germany).

1861 Rubidium discovered by Gustov Kirchhoff and Robert Bunsen (Germany).

1861 Thallium discovered by Sir William Crookes (England).

1863 Indium discovered by Ferdinand Reich and H. Richter (Germany).

1865 H. Geissler and J. Plucker observe fluorescence in evacuated tubes containing electrodes.

1868 (Mar 22) Robert Millikan is born.

1869 (Feb 14) C.T.R. Wilson is born.

1869 E. Goldstein coins phrase "cathode rays."

1869 Hittorf shows cathode emanation stopped by solid object.

1869 William Crookes notes fogging in photographic plates in his laboratory and complains of defective packaging. The fogging is actually caused by an unknown at the time radiation, x-rays, produced in Crookes' tubes.

1870 James Maxwell puts forth an extension of the theories of Michael Faraday and Orsted in a rigorous mathematical form: charge and the electric field; the magnetic field; magnetic effect of a charging electric field or moving charge; and the electric effect of a changing magnetic field.

1871 Ernest Rutherford is born.

1872 (July) Dmitri Ivanovitch Mendeleev, an unknown Siberian supervisor of weights and measures, presents paper in St. Petersburg detailing his Periodic Table of the Elements.

1873 (Oct 23) William Coolidge is born.

1875 Gallium discovered by Paul Emile Lecoq de Boisbaudron (France).

1876 Eugen Goldstein (Germany) coins the phrase "cathode rays."

1878 Holmium discovered by J.L. Soret (Switzerland).

1878 Ytterbium discovered by Jean de Marignac (Switzerland).

1879 (Mar 8) Otto Hahn is born.

1879 (Mar 14) Albert Einstein is born.

1879 W. Crookes shows cathode rays are solid matter with sufficient energy to drive a small wheel.

1879 Identification of the malady in Schneeberg mines as lung cancer. Thought to be lymphosarcomata, the causation remains murky.

1879 Scandium discovered by Lars Nilson (Sweden).

1879 Samarium discovered by Paul Emile Lecoq de Boisbaudron (France).

1879 Thulium discovered by Per Theodor Cleve (Sweden).

1880 Gadolinium discovered by Jean de Marignac (Switzerland).

1881 George Johnstone Stoney (Ireland) names the indivisible unit of electricity the electron.

1882 (Sept 30) Hans Geiger is born.

1883 (June 24) Victor Hess is born.

1884 Balmer (Switzerland), a high school teacher, finds that gases bombarded by electrons will emit electromagnetic waves of only certain wavelengths which he measures with a grating spectroscope.

1884 Joseph John Thomson, aged 28, becomes Director of the Cavendish Laboratory at Cambridge University.

1885 (Aug 1) George de Hevesy is born.

1885 (Oct 7) Niels Bohr is born.

1885 Praseodymium discovered by C.F. Aver von Welsbach (Austria).

1886 H. Hertz characterizes long wave electromagnetic radiation.

1886 Goldstein notices rays going the opposite way from cathode rays channeling through a hole in the cathode. He names them "channel rays." These are later found to be the positive ions of the wisps of gas in the tube or parts of the cathode.

1886 Fluorine discovered by Henri Moissan (France).

1886 Germanium discovered by Clemens Winkler (Germany).

1886 Dysprosium discovered by Paul Emile Lecoq de Boisbaudron (France).

1887 (Nov 23) Henry Moseley is born.

1890 (Mar 31) W.L. Bragg is born.

1890 (Dec 21) Hermann Muller is born.

1891 (July 10) Edith Quimby is born.

1891 H. Hertz, assisted by P. Lenard, studies the penetrating power of cathode rays.

1894 Argon discovered by Sir William Ramsey and Baron Rayleigh (Scotland).

1895 (July 26) Marie and Pierre Curie marry.

1895 (Sept 2) Otto Glasser is born.

1895 (Nov 8) Roentgen discovers X-rays.

1895 (Dec 22) Roentgen X-radiodiographs his wife's hand.

1895 (Dec 28) Roentgen communicates the discovery of X-rays to the Wurzburg Society.

1895 Helium discovered by William Ramsey, Nilo Langet, and P.T. Cleve (Scotland and Sweden).

1895 Rutherford shows that "uranium emanation" has a spectral line of helium

1895-1900 Photographic emulsions and electroscopes are primary instruments used when radiation is discovered.

1896 (Jan 1) Roentgen sends radiographs to colleagues.

1896 (Jan 5) First newspaper account of X-rays is published.

1896 (Jan 6) The discovery of X-rays is cabled world-wide by the London Times.

1896 (Jan 7) Campel-Swinton make radiograph in UK.

1896 (Jan 23) Roentgen makes first demonstration regarding X-rays.

1896 (Jan 27) Arthur Wright produces radiograph at Yale University.

1896 (Jan 29) First therapeutic applications of X-rays (Grubbe, Voigt, Despeignes)

1896 (Feb 3) First diagnostic X-ray by Edwin Frost (US) & John Cox (Canada).

1896 (Feb) First x-ray picture of a fetus in utero.

1896 (Mar 1) X-rays are used by Italian army.

1896 (Mar 3) Becquerel demonstrates the radioactivity of uranium.

1896 (Mar) First application of X-rays in dentistry (C. Kells and W. Rollins).

1896 (Mar) Thomas Edison reports eye injuries from X-rays.

1896 (June) N. Tesla cautions experimenters not to get too close to X-ray tubes.

1896 Dr. D. W. Gage (McCook, NB.) writing in New York's "Medical Record," notes cases of hair loss, reddened skin, skin sloughing off, and lesions. "I wish to suggest that more be understood regarding the action of the x rays before the general practitioner adopts them in his daily work."

1897 (Sept 12) Irene Curie is born.

1897 (Nov 18) P. M. Blackett is born.

1897 (Jan 18) Roentgen Society of London is organized.

1897 J.J. Thomson demonstrates corpuscular nature of cathode rays. He theorizes that these electrons might be a constituent part of all matter. He reports the mass of the electron.

1898 (Feb 11) Leo Szilard is born.

1898 (Mar) Discovery of radioactivity of thorium by G. Schmidt.

1898 (Apr 12) Marie Sklodovska Curie announces the probable presence in pitchblende ores of a new element endowed with powerful radioactivity.

1898 (July 13) Polonium isolated from pitchblende by Marie & Pierre Curie.

1898 (July) Marie & Pierre Curie coin word "radioactivity."

1898 (Dec 26) Radium-226 isolated from pitchblende by Marie & Pierre Curie.

1898 Becquerel receives skin burn from radium given to him by the Curies that he keeps in his vest pocket. He declares, "I love this radium but I have a grudge against it!"

1898 Neon discovered by Sir William Ramsey and M.W. Travers (England).

1898 Krypton discovered by Sir William Ramsey and M.W. Travers (England).

1898 Xenon discovered by Sir William Ramsey and M.W. Travers (England).

1899 Radioactive gaseous emanation from thorium is described by Rutherford.

1899 Andre Louis Debiere (France) discovers actinium, a radioactive element (atomic number 89.)

1899 Rutherford finds two kinds of radiation, which he names alpha and beta, emitted from radium.

1900 Crookes shows that purified uranium has almost no radioactivity. He suggests that uranium was not the origin of the radiation but some impurity in the uranium.

1900 Discovery of gamma rays by P. Villard.

1900 Thorium-234 discovered by Crookes.

1900 American Roentgen Ray Society (ARRS) founded.

1900 Friedrich Ernst Dorn discovers radon (atomic number 86), a radioactive daughter of uranium.

1900 Thorium beginning of use in gas mantles.

1900 Marie Curie explains natural transmutation as a decay of an unstable atom to one of a lower atomic weight.

1900 Planck's constant, h = 6.63 E-34 J s, is published.

1900 Thomson's "plum pudding" model of the atom is proposed.

1900-1924 Gradual development of mechanical electrometers.

1901 (Jan 3) First report of death due to X-rays is published.

1901 Becquerel confirms Crookes' statement about uranium not being the origins of the radiation but also shows that if uranium is left standing, its radioactivity increases.

1901 Europium discovered by Eugene Demarcay (France).

1901 Max Planck proposes that atoms could gain and lose energy only in discrete quantities (quantum).

1901 First Nobel prize in physics is awarded to Roentgen.

1902 (Apr) Radioactive spontaneous disintegration, the unaided transmutation of elements, observed and named by Soddy and Rutherford.

1902 (June 1) Lauriston Taylor is born.

1902 Radium-224 (thorium X) discovered by Soddy and Rutherford.

1902 Rollins experimentally shows X-rays can kill higher life forms.

1902 Existence of radium verified by Curies by chemical methods; they obtain 0.1 g of pure radium from several tons of pitchblende.

1903 (June 25) Marie Curie accorded the title of doctor of physical science, with the mention of très honorable from the University of Paris, Sorbonne

1903 (Nov 12) Marie and Pierre Curie awarded the Nobel Prize for Physics.

1903 Sir William Crookes and, independently, Elster and Geitel discover that crystals of zinc sulfide emit tiny flashes of visible light (scintillations) when struck with alpha particles. Rutherford quickly adopts this detector for his work.

1904 (Apr 22) J. Robert Oppenheimer is born.

1904 (Oct) Clarence Madison Dally, a glass blower at Thomas Edison's Menlo Park lab, is first person known to have been killed by x-ray exposure. Severely burned in 1896, he still works with x-rays until 1898. His death causes Edison to discontinue radiation work in his lab.

1904 Rutherford shows that alpha particles are helium atoms and works out the natural decay series.

1904 Radon and daughters identified as part of the uranium series. Work with animals begins, especially in Russia and France.

1904 Colormetric dosimetry system devised by Saboroud and Noire.

1904 Marie Curie publishes an observation that diamonds when exposed to radiation and later heated glow proportional to exposure. This is published in Research on Radioactive Substances . This is the basis for thermoluminescent dosimetry which waits until 1950 to be further developed.

1904 "If it were ever possible to control at will the rate of disintegration of radio elements, an enormous amount of energy could be obtained from a small amount of matter." --Ernest Rutherford.

1904 H. Nagaoka (Japan) publishes planetary hypothesis of atomic structure.

1904 Rutherford coins the term "half-life."

1905 (June 6) "Is it right to probe so deeply into Nature's secrets? The question must here be raised whether it will benefit mankind, or whether the knowledge will be harmful. Radium could be very dangerous in criminal hands. Alfred Nobel's discoveries are characteristic; powerful explosives can help men perform admirable tasks. They are also a means to terrible destruction in the hands of the great criminals who lead peoples to war..." Pierre Curie in his Nobel Prize Oration delayed from 1903.

1905 (Sept 3) Carl Anderson is born.

1905 Einstein publishes Special Theory of Relativity E= mc2

1905 Einstein explains the Photoelectric Effect by introducing light quanta (photons of energy E = hv)

1905 Thorium-228 discovered by Hahn.

1905 Ionization unit proposed by M. Franklin.

1905 Boltwood calls attention that lead is found with uranium and suggests that lead might be the end product of uranium.

1906 (April 19) Pierre Curie killed by a horse-drawn wagon filled with military uniforms driven by Louis Manin on the streets of Paris, France.

1906 Ernest Rutherford conducts experiments where he bombards gold foil with alpha particles. Most of the alphas pass through. He theorizes that atoms are mostly space.

1906 Joseph John Thomson is awarded the Nobel Prize in physics for his theoretical and experimental investigations into the electron and the conduction of electricity by gases.

1907 (May 18) Robley Evans is born.

1907 Ionium (Th-230) discovered by Boltwood.

1907 Lutetium discovered by Georg Urbain (France).

1907 H. N. McCoy and W. H. Ross at the University of Chicago show that two different radioelements might be chemically identical.

1908 Ernest Rutherford is awarded the Nobel Prize in chemistry for his observations on radionuclide decay (transmutation).

1909 Ernest Rutherford observes one alpha particle in 8000 being bounced back from a thin gold foil. From this observation, he concludes that most of the atom's mass is conentrated in a small postively-charged nucleus.

1909 Robert Andrews Millikan using oil droplets measures the charge of an electron e= 1.60 E-19 C.

1910 (Apr 13) Herbert Parker is born.

1910 Curie unit defined as activity of 1 gram of radium.

1910 Soddy establishes the existence of isotopes, nuclides with the same number of protons but different number of neutrons.

1910 Animal work on distribution and excretion of radium (mostly in Europe). Radium begun to be used as nostrum.

1910 Jesuit Father Theodor Wulf measures radiation at ground level and at top of Eiffel Tower. Radiation increases at higher elevation. Suspects extraterrestrial origins of this radiation. Suggests balloonists measure dose rates.

1911 (Aug) Rutherford and Geiger discover that atoms are mostly space using alpha particles to bounce off thin gold foil.

1911 Marie Curie awarded the Nobel Prize for Chemistry for the separation of radium from pitchblende.

1911 Soddy suggests that "the expulsion of the alpha particle causes the radioelement to change its position on the periodic table..."

1911 Charles Glover Barkla (England) shows certain x-rays predominate; these are termed characteristic x-rays.

1911 Microscope is used to count grain densities in photographic film.

1911 Charles Thomas Rees Wilson (Scotland) invents the cloud chamber which shows tracks of radiation in a supersaturated atmosphere.

1911 Georg von Hevesy (Hungary) conceives the idea of using radioactive tracers. Leads to Nobel Prize in 1943.

1911-1912 Victor Hess (Austrian) takes balloon rides to measure radiation at heights up to 5000 meters. Discovers cosmic radiation which he names "Hoehenstrahlung" (high altitude rays.)

1912 (July 16) Patent granted to the Radium Ore Revigorator Co., 260 California St., San Francisco, CA for a device, the Revigorator, that charges water with radon, ushering in a 20-year craze in radioactive health crocks. Instructions read: "Fill jar every night, use hydrant or any good water, drink freely when thirsty and upon rising and retiring. Average six or more glasses daily. Scrub with stiff brush and scald monthly."

1912 Arthritis patient dies because of Ra-226 injections.

1912 T. Christen puts forth concept of half value layer for shielding x or gamma radiation, i.e., only half the incident radiation will be stopped by each successive shielding layer.

1912 Max von Laue (Germany) uses the crystals of zinc sulfide to diffract x-rays and measure their wavelength. He thereby proves the wavelike nature of x-rays.

WW I Exposure of hundreds of girls to luminous paint compound for instrument dials in New York and Illinois.

WW I Henry Gwyn-Jeffries Mosley killed at Gallipoli. Mosley, a student of Rutherford, had bombarded each of the known elements with a beam of electrons to show the number of electric charges in each nucleus was increased in regular steps between each element in the periodic table.

1913 (Jan 31) A. S. Russell put forward that in beta decay the position of the element in the periodic table changes by one place.

1913 Hans Geiger unveils his prototype gas-filled radiation detector.

1913 Niels Bohr (Denmark) applies the newly invented quantum theory to atomic electron orbitals. These stationary orbitals would allow an electron to orbit a nucleus without emitting energy.

1913 Soddy proposes the term "isotope" for atoms with the same number of protons and differing only in number of neutrons.

1914 H.G. Wells publishes The World Set Free set in 1956 predicts an alliance of England, France, and America against Germany and Austria. All the major cities of the world are destroyed by atomic bombs.

1914 Ernest Marsden, Rutherford's assistant, reports an odd result when he bombards nitrogen gas with alpha particles -- something is thrown back with much greater velocity. This is the first report of nuclei fissioning.

1914 Franck-Hertz experiment demonstrates discrete atomic energy levels in collisions with electrons.

1915 (June) British Roentgen Society proposes standards for radiation protection workers; includes shielding, restricted work hours, medical exams; no limits because of lack of units for dose or dosimeters; voluntary controls. This is believed to be the first organized step toward radiation protection.

1915 (Aug) Robert Rich Sharp discovers the Shinkolobwe uranium deposit in the Congo. Mine averages 68% uranium; richest find in history and is on the surface.

1916 A. Sommerfeld (Germany) modifies Bohr's model of electron orbitals to allow elliptical orbits.

1917 Otto Hahn and Lise Meitner discover protactinium.

1919 First artificial transformation of an element by performed by Rutherford, now Director of Cavendish laboratory; alpha particle on nitrogen causes the expulsion of oxygen and hydrogen.

1920 Luminous dial painting expanded to clock factories.

1920 American Roentgen Ray Society (ARRS) establishes standing committee for radiation protection.

1920 Rutherford suggests additional neutral nuclear particle (later called a neutron). "Such an atom would have very novel properties. Its external field would be practically zero, except close to the nucleus, and, in consequence, it should be able to move freely through matter."

1920 James Chadwick in Rutherford's lab uses alpha particle scattering to determine the charges on the nucleus of copper, silver, and platinum.

1920-1930s Much use of radon generators in hospitals for preparation of radon seeds.

1921 Suggestion that radium and radium emanation might be causative agent in cancer in miners taken seriously but not proven.

1921 British X-ray and Radium Protection Committee present its first radiation protection standards.

1922 American Roentgen Ray Society adopts radiation protection rules.

1922 Niels Bohr is awarded the Nobel Prize in physics for describing how orbital electrons absorb and emit energy.

1922 American Registry of X-ray Technicians founded.

1922 G. Pfahler recommends personnel monitoring with film.

1922 P. Auger and F. Perrin determine the charge on the nucleus of argon.

1922-1924 Suspicions develop around radium dial painter's jaw lesions.

1923 (Jan 30) Szamatolski links dial painter injuries to radium.

1923 (Feb 10) Wilhelm Roentgen dies.

1923 A.H. Compton reports wavelengths lengthened for bounced x-rays and gammas. Leads to Nobel prize for the "Compton Effect".

1923 A. Mutscheller puts forth first "tolerance dose" (0.2R/day).

1923 "There is no likelihood man can ever tap the power of the atom... Nature has introduced a few foolproof devices into the great majority of elements that constitute the bulk of the world, and they have no energy to give up in the process of disintegration."--Dr. Robert Andrews Millikan

1923 Hafnium discovered by Dirk Coster and Georg von Hevesy (Denmark).

1924 Description of jaw necrosis by dentist, Blum; attributed to radiation from deposited luminous paint.

1924 DeBroglie states that an electron has wave properties and assigns a wavelength to an electron much the same way Einstein assigns a mass to an electromagnetic wave in 1905. This standing wave allows an electron to exist a some distance from the nucleus without gaining or losing energy.

1924 Uhlenbeck and Goudsmit ascribe electron with intrinsic spin h/2.

1925 (July 1) First International Congress of Radiology is held, establishes International Commission on Radiological Units (ICRU).

1925 Physician, Martland, describes pathology of bone changes and anemia in radium dial painters.

1925 William Bailey introduces Radithor, a quack radium potion to cure sexual dysfunction and everything else.

1925 Rhenium discovered by Walter Noddak, Ida Takke, and Otto Berg (Germany).

1925 Mutscheller's "tolerance dose" for X-rays.

1925 Neodymium discovered by C. Aver von Welsbach (Austria).

1925 Pauli explusion principle states that two electrons cannot share orbitals and spin in the same atom at the same time.

1925 Heisenberg's first paper on quantum mechanics.

1925-1929 The saga of radium dial painters and iatrogenic cases unfolds.

1926 (July) "Radium Treatment of Carcinoma of the Lower Lip" is published in Radiology, Vo. VII, No. 1.

1926 (Aug) "Radiation of Cancer of the Cheek" is published in Radiology, Vol. VII, No. 2.

1926 (Oct) "Treatment of Lingual Cancer by Radiation" is published in Radiology, Vol. VII, No. 4.

1926 (Oct) "The Treatment of Bladder Tumors with Metal Seeds Containing Radium Emanation" by Dr. Edward L. Keyes is published in The Journal of Medical Society of New Jersey.

1926 (Nov) "Radium Therapy in Rhinology" is published in Radiology, Vol. VII, No. 5.

1926 (Dec) "Radiation of Malignancy of the Maxillary Sinus" is published in Radiology, Vol. VII, No. 6.

1926 (Dec) "Irradiation of Diseased Tonsils" is published in Medical Journal & Record, 124:873.

1926 Erwin Shrodinger publishes the wave theory of matter demonstrating that matter at the atomic level behaves as it consists of waves.

1926 Edith Quimby devises film badge dosimeter with energy compensating filters.

1927 (Feb) Werner Heisenberg realizes that it is impossible to establish at any given instant both the momentum and location of a subatomic particle. This is published as his Uncertainty Principle.

1927 (Sept) "Malignancy of the Larynx and Esophagus Treated by Radium Emanation" by Dr. Frank Richard Herriman is published in The Laryngoscope.

1927 Dutch Board of Health recommends tolerance dose equivalent to 15 R/year.

1927 H. Muller shows genetic effects of radiation.

1927 Herman Blumgart, a Boston physician, first uses radioactive tracers to diagnose heart disease.

1927 Birth of quantum electrodynamics, Dirac's paper on "The Quantum Theory of the Emission and Absorption of Radiation."

1928 Organization and first meeting of International Committee on X-ray and Radium Protection (predecessor of ICRP).

1928 Description of basis for Geiger-Mueller counter by Hans Geiger and Walter Mueller at the Physics Institute in Kiel (Germany).

1928 Second International Congress of Radiology establishes International Committee on X-ray and Radium Protection (predecessor of ICRP) and publishes first set of international radiation protection standards; Roentgen unit accepted.

1928 Organization of US Advisory Committee on X-ray and Radium Protection (predecessor of NCRP).

1928 Dirac's relativistic wave equation of the electron.

1929 R. d'E. Atkinson and F. G. Houtermans (Germany) theorize that energy from stars is a result of nuclear fusion.

1929 "The energy available through the disintegration of radioactive or any other atoms may perhaps be sufficient to keep the corner peanut and popcorn man going in our large towns for a long time, but that is all." --Dr. Robert A. Millikan (hedging a bit on his statement of 1923).

1929 "Free air" ionization chambers used as primary standards.

1929 Nuclear track photographic plates developed.

1929 Osteogenic sarcoma (bone cancer) is proven in the dial-painter population.

1929 Advisory Committee on X-Ray and Radium Protection (ACXRP) formed in the US (forerunner of NCRP).

1929-1930 Fifty percent of miners dying at Joachimsthal have carcinoma of lung.

1929-1933 Collaborative work by Schlundt, Failla, et al, on radium metabolism in patients at Elgin State Hospital in Illinois.

1930 Bothe and Becker find that after bombarding beryllium with alpha particles a very penetrating, uncharged type of radiation is produced. They assume, wrongly, that it must be an electromagnetic wave. It is later proven by Chadwick to be the neutron.

1930 Invention of the cyclotron by E. O. Lawrence & MS Livingston at Berkeley.

1930 Bethe quantum-mechanical stopping-power theory.

1930s Vacuum-tube electrometers gradually replace mechanical ones.

1930 Early count rate meter invented.

1931 (Jan 2) Lawrence operates first cyclotron.

1931 (May 16) NBS Handbook 15 is published.

1931 Van de Graaff electrostatic generator constructed.

1931 Linear accelerator is constructed by Sloan & Lawrence at Berkeley.

1931 "Alpha particles are probably the most potent and destructive agent known to science"--Martland

1931 The Roentgen adopted as unit of X radiation.

1932 (Feb 17) Chadwick discovers the neutron using Bothe and Becker’s experimental set up. He scoops the Joliot-Curies who believed their "beryllium rays" were another form of electromagnetic radiation.

1932 (Mar) Eben Byers, prominent Pennsylvania industrialist and playboy millionaire, dies of the effects of drinking "Radithor." Others follow.

1932 (Aug 2) Carl Anderson using a specially prepared cloud chamber discovers a particle with the same mass and opposite charge as an electron (positron) in cosmic rays. He wins the Nobel Prize for his discovery in 1936.

1932 "There is not the slightest indication that nuclear energy will ever be obtainable. It would mean that the atom would have to be shattered at will." --Dr. Albert Einstein

1932 G. Failla suggests limit of 0.1 R/day to whole body and 5 R/day to fingers; introduces concept of higher permissible dose to limited portions of body.

1932 Roentgen unit is defined as producing one E.S.U. of either sign in 1 cc of air at STP.

1932 Werner Heisenberg proposes that the nucleus is composed only of protons and neutrons.

1933 (Sept 12) Leo Szilard envisions nuclear chain reaction.

1933 (Sept 12) "The energy produced by the atom is a very poor kind of thing. Anyone who expects a source of power from the transformation of these atoms is talking moonshine." --Lord Ernest Rutherford (after splitting the atom for the first time)

1933 (Oct) The 7th Solvay Conference in Brussels, Belgium is devoted to nuclear physics for the first time. Attendees include: Marie Curie, Rutherford, Bohr, Lise Meitner, Heisenberg, Pauli, Enrico Fermi, Chadwick, George Gamow, Irene and Frederic Joliot-Curie, Patrick Blackett, Rudolf Peierls, Ernest Lawrence.

1933 DuBridge and Brown compensating circuit, vital for gas-filled radiation detectors, is invented.

1933 First effort to reduce radium body burden by manipulation of diet and administration of parathyroid hormone.

1934 (Jan 11) First artificially produced radionuclide (P-30 from aluminum bombarded with Polonium alpha particles) by Irene Curie and J. F. Joliot, Paris.

1934 (Mar 12) Szilard applies for a patent, "Improvements in or Relating to the Transmutation of Chemical Elements," stating "In accordance with the present invention radio-active bodies are generated by bombarding suitable elements with neutrons... Such uncharged nuclei penetrate even substances containing the heavier elements without ionization losses and cause the formation of radio-active substances."

1934 (June 28 & July 4) Szilard amends his patent to add "the liberation of nuclear energy for power production and other purposes through nuclear transmutation." He hypothesizes, "a chain reaction in which particles which carry no positive charge and the mass of which is approximately equal to the proton mass or a multiple thereof (i.e. neutrons) form the links of the chain." He describes the concept of critical mass and of reflecting neutrons back into the mass. Further, "if the thickness is larger than the critical value... I can produce an explosion."

1934 (July 4) Marie Curie (born Nov 7, 1867) dies in Sancellemoz, France. The disease is aplastic pernicious anemia of rapid, feverish development.

1934 Fermi mistaken reports new element after bombarding uranium with neutrons. Ida Noddack suggests Fermi split the atom; this is ignored.

1934 Evans at MIT starts whole body counting.

1934 Production and use of radiosodium.

1934 "Tolerance Dose" of 0.1 R/day, measured in air, recommended by Advisory Committee on X-ray and Radium Protection.

1934 "Tolerance Dose" of 0.2 R/day, measured at the surface of the body, recommended by the International Committee on X-ray and Radium Protection.

1934 Enrico Fermi works out theory for beta minus decay.

1934 H. Urey discovers deuterium.

1934-1939 Measurements begin on radium content of natural waters.

1935 G. von Hevesy performs first radioisotope tracer studies using P-32 to measure water turnover rates in goldfish.

1935 Hans Bethe reports new ideas on the prospect of capture by the uranium nucleus of a neutron slowed by collision with hydrogen.

1935 Neils Bohr conceives the "water droplet" model of the nucleus.

1935 Irene and Frederic Joliot-Curie win the Nobel Prize in Physics.

1935 Compton and Allison state, "Though it is usually employed to give only qualitative results, the photographic plate can also be adapted to precise quantitative comparisons of x-ray intensities."

1935 Yukawa predicts the existence of mesons, reponsible for the short-range nuclear force.

1936 Bragg-Gray principle of charged particle radiation interaction with matter formed.

1936 Victor Hess receives Nobel Prize for cosmic rays.

1936 First use of radioisotopes in therapy by John Lawrence (Berkeley); produced in 37 inch cyclotron; P-32 used on polycythemia vera.

1936 H. Yukawa and S. Sakata (Japan) predict electron capture process to compete with positron emission.

1936-1940 Use of radioiodine from MIT cyclotron. Patients at Mass. Gen. Hosp.

1936-1941 Rat work at MIT on radium but rats more resistant than man to radium effect.

1937 (Oct 19) Sir Ernest Rutherford (born 1871) dies, his ashes are placed in a corner of Westminster Abbey next to the grave of Isaac Newton.

1937 Lauritsen electroscope used to measure dose.

1937 Extrapolation chamber invented by Failla.

1937 Technetium discovered by Carlo Perrier and Emillo Segre (Italy).

1937 Mesons found in cosmic rays.

1938 (Dec) Nobel Prize awarded to Enrico Fermi (Italy) for his work on transuranics. The Fermi family (Laura, Enrico's wife, is Jewish) escapes from Italian Nazi persecution to New York.

1938 Electron capture radionuclides discovered by L. W. Alvarez (USA).

1938 Tritium discovery by Alvarez & Cornog; produced in accelerators.

1938 Hahn and Strassman split the atom repeating Fermi's work.

1939 (Jan 6) Hahn and Strassman's experimental results of fissioning uranium published in "Die Naturwissenschaften."

1939 (Jan 13) Frisch offers experimental proof of fission in a Geiger counter.

1939 (Jan 26) Fermi announces uranium releases a few neutrons on splitting. He speculates upon the possibility of a chain reaction.

1939 (March 3) Szilard and Zinn prove possibility of chain reaction by performing experiment in Pupin Hall, Columbia University which shows many neutrons are released during fission of uranium.

1939 (March 16) Hitler annexes Czechoslovakia, richest known source of uranium.

1939 (April 29) First official conference on fission is held in Berlin Germany by the Reich Ministry of Education.

1939 (April) The Joliot-Curies publish a report confirming Szilard and Zinn's finding of neutrons released by uranium fission.

1939 (April) Uranverein ("uranium club") founded in Berlin to do work on uranium fission.

1939 (Aug 2) Einstein signs letter, drafted by Leo Szilard and Eugene Wigner, to Roosevelt alerting him to the feasibility of building an atomic bomb and the threat of Germany building one.

1939 (Sept 3) Germany declares war on Great Britain.

1939 (Oct 21) Uranium Committee, appointed by Roosevelt, holds first meeting.

1939 Igor Kurchatov alerts the USSR government of the military significance of nuclear fission.

1939 Correct description of phenomena of nuclear fission by Meitner and Frisch (Germany).

1939 Enrico Fermi patents first reactor (conceptual plans).

1939 Binary scaler introduced as auxiliary pulse-counting equipment.

1939 More useful count rate meter developed.

1939 Francium discovered by Marguerite Duray (France).

1940 (July 15) Kerst operates first betatron.

1940 (Nov 8) First contract is signed with Columbia University to develop bomb material.

1940 Neptunium-239 discovered by E.M. MacMillan and P.H. Abelson (United States) at Berkeley.

1940 George Flerov of the USSR discovers the spontaneous fission of uranium.

1940 Photomultiplier tube is developed by Larson and Salinger which makes scintillation radiation detectors much more useable.

1940 Astatine discovered by D.R. Corson, K.R. MacKenzie, and E. Segre (United States).

1940s Enormous strides in ion chambers, vacuum tube electrometers, improved G-M tubes, pulse counting, discriminators, linear amplifiers, autoradiography, etc., taken under Manhattan Engineering District (MED) auspices.

1940 Radiation pneumonitis is described by Warren & Gates.

1940 Joseph John Thomson dies.

1941 (Feb 25) Plutonium 238 isolated by G.T. Seaborg, J.W. Kennedy, E.M. MacMillan, and A.C. Wohl (United States) at Berkeley from products of neptunium decay.

1941 (Sept 18) Werner Heisenberg meets with Neils Bohr to try to convince Bohr and the Western Allies that atomic bomb production is unfeasible and should be stopped. Bohr is unconvinced and suspects Heisenberg's, now working for the Nazis, motives.

1941 Max Permissible Body Burden set at 0.1 uCi for radium recommended by Advisory Committee on X-ray and Radium Protection based on radium dial painters.

1941 First standard for radon (10-11 Ci/l), Evans and Goodman National Bureau of Standards report.

1941 Pecher (Berkeley) finds that radiostrontium behaves like calcium and deposits in bone.

WW 2 Animal work at U. of Rochester on rat with radium excretion.

1942 (Jan 24) A. H. Compton, chairman of the Physics Department at University of Chicago, announces his decision to site the first self-sustaining chain reaction at University of Chicago. This is over the objections of Szilard (Columbia U.) and Lawrence (Berkeley).

1942 (June 23) Werner Heisenberg's fourth experimental atomic pile, the L-IV, explodes spewing burning particles of uranium twenty feet in the air and catching the lab on fire. Heisenberg and Robert Doepel are nearly killed.

1942 (Aug 25) Entire world's supply of plutonium spilled and recovered from soggy copy of Chicago Tribune (Met Lab).

1942 (Sept) The Manhattan Project is formed to secretly build the atomic bomb before the Germans.

1942 (Nov 16) Construction begins on Chicago Pile 1 (CP-1) begins.

1942 (Nov) Los Alamos is selected as site for atomic bomb laboratory. Robert Oppenheimer is named director.

1942 (Dec 2) First sustained and controlled chain reaction in an atomic pile at University of Chicago. Reactor is graphite moderated. Fermi oversees design and building. Fission products expected. Arthur Compton sends message to James Conant: "The Italian navigator has arrived at the shores of the new world and found the natives were friendly. It is a smaller world than he believed."

1942 Beginning of biomed work at Chicago's Michael Reese Hospital on uranium (cells & whole organism).

1942-1943 Concern develops at Metallurgical Laboratory (Chicago) about potential hazards of radioxenon & I-131 and fission products.

1942-1945 Concern over possible use of fission products in radiological warfare leads to Projects Peppermint and Gabriel (secret study on fallout effects).

1943 (Apr 1) The security gates begin operating at Oak Ridge, TN.

1943 (Apr) Ground broken for Hanford reactors, built to produce plutonium for Nagasaki bomb.

1943 (Nov 4) Oak Ridge X-10 Clinton reactor goes into operation at Oak Ridge; first to generate electricity with a model steam engine.

1943 Uranium toxicology studies at U. of Rochester.

1943-1947 Polonium injected into incurable patients at Rochester, NY. Potential doses greater than occupational limits.

1944 (Sept 27) Hanford reactor 100B achieves criticality.

1944 Substantial group begins work at Met Lab (Chicago) on biomedical aspects of fission products.

1944 Air limits for plutonium-239 derived by H. Parker at Met Lab.

1944 Curium discovered by G.T. Seaborg, R.A. James, A. H. Ghiorso (United States).

1945 (May 14) Plutonium injected IV into human subjects at Los Alamos. Eighteen subjects injected that year.

1945 (June 6) Criticality accident at Los Alamos, 14 people exposed, some up to 3000 rem gamma and neutrons.

1945 (July 16) Trinity Test (Alamagordo, NM) cattle receive beta burns. 19 KT yield. First atomic bomb.

1945 (July) Szilard writes Roosevelt warning of arms race: "The development of atomic power will provide the nations with new means of destruction. The atomic bombs at our disposal represent only the first step in this direction, and there is almost no limit to the destructive power which will become available in the course of their future development. Thus a nation which sets the precedent of using these newly liberated forces of nature for purposes of destruction may have to bear the responsibility of opening the door to an era of devastation on an unimaginable scale."

1945 (Aug) Photographic film at Eastman Kodak fogged from contaminated packing paper (fallout from Trinity).

1945 (Aug 6) Hiroshima, Japan, is atomic bombed.

1945 (Aug 9) Nagasaki, Japan, is atomic bombed.

1945 (Aug 21) Harry Daghlian, a Los Alamos lab tech, conducts an unauthorized experiment and is lethally irradiated; first North American to die of acute radiation sickness.

1945 (Sept 5) The ZEEP reactor (1st outside of US) achieves first self-sustaining fission chain reaction in Canada.

1945 (Sept) USSR occupies Czechoslovakia. Soviet commanders order all German plans, parts, models, and formulas regarding the use of atomic energy, rocket weapons, and radar be turned over to them. USSR infantry and technical troops occupy Jachimov and St. Jaochimstal (the only European source of uranium.)

1945 (Dec 24) An attaché at the US Embassy in Moscow warns that "the USSR is out to get the atomic bomb. This has been officially stated. The meager evidence available indicates that great efforts are being made and that super-priority will be given to the enterprise."

1945 Landmark paper published by Cantril and Parker on tolerance dose.

1945 K. Z. Morgan circulates first comprehensive calculations of maximum permissible body contents and concentrations in air and water for many radionuclides in a Met Lab Report called "Tolerance Concentrations."

1945 Standards developed for plutonium on basis of animal toxicity data. Earliest attempts are on basis of half-life relative to radium, but animal work proves this to be incorrect.

1945-1946 Inhalation experiments at Rochester made basis for revision of standard for uranium. Different levels recommended for soluble versus insoluble salts.

1945-1947 18 patients (one a five year old) injected with plutonium at Rochester, NY, Oak Ridge, TN., U. of Chicago, and UCSF. No informed consent; potential doses much greater than occupational limits.

1945 Promethium discovered by J. A. Marinski, L. E. Glendenin, C.D. Coryell (United States).

1945 Americium discovered by G.T. Seaborg, R.A. James, L. O. Morgan, and A. Ghiorso (United States).

1946 (May 21 <3:20 PM>) 32 year old man (Louis Slotin) receives an estimated 1100 to 2200 rad whole body, 30,000 rad on hands, of mixed neutron and gamma radiation while "tickling the dragon's tail" (hand lowering beryllium reflector around plutonium bomb core); dies nine days later of GI tract syndrome. Bomb core was the same as the one that killed Daghlian. Seven others exposed but none fatally.

1946 (June - July) Crossroads bomb tests at Bikini includes 20 kT underwater burst "Baker".

1946 (July 24) Test-shot Baker 21 kT at Bikini.

1946 (Aug 1) Atomic Energy Act is passed; establishes AEC and JCAE.

1946 (Aug) The Oak Ridge facility ships the first nuclear reactor-produced radioisotopes for civilian use to the Barnard Cancer Hospital in St. Louis, Mo.

1946 Dr. Helmuth Ulrich publishes study in "New England Journal of Medicine" showing leukemia rate among radiologists to be eight times that of other doctors.

1946 Reorganization of US Advisory Committee. Renamed National Committee on Radiation Protection and operates out of the Bureau of Standards. Has two subcommittees on radionuclide problems.

1946 US starts nuclear bomb tests in the South Pacific.

1946 Fission products investigated as carcinogenic agents in Chicago.

1946 Hanford establishes a Biology Section under Radiological Sciences Division.

1946-1947 Six patients injected with enriched uranium nitrate at Rochester. Some doses produced kidney damage.

1947 (Jan) Reports about some of the US human radiation experiments, originally classified, are declassified apparently at the suggestion of the researchers involved.

1947 (Feb 26) C.L. Marshall, an AEC deputy declassification officer, writes, "This document appears to be the most dangerous since it describes experiments performed on human subjects, including the actual injection of the metal, plutonium, into the body. Unless, of course, the legal aspects were covered by the necessary documents, the experimenters and the employing agencies, including the U.S., have been laid open to a devastating lawsuit which would ... have far-reaching results. The coldly scientific manner in which the results are tabulated and discussed would have a very poor effect on the general public." No mention is made to any perceived need for withholding information for national security purposes.

1947 (May) AEC chairman David Lillienthal convenes a group of senior researchers to develop recommendations on the new agency's policies on medical research.

1947 (June) "Secrecy in research is distasteful," the AEC’s medical research advisory group declares in a report, "and in the long run is contrary to the best interests of scientific progress."

1947 (Dec 22) "... an education program must be organized so that each person engaged in work that involves radiation exposure may be taught to appreciate the problems of radiation protection, and learn to consider it a personal responsibility to see that he and all those with whom he works are protected adequately from radiation hazards." -- K.Z. Morgan, Clinton National Laboratory.

1947 US National Academy of Sciences establishes Atomic Bomb Casualty Commission (ABCC) to initiate long-term studies of A-bomb survivors in Hiroshima and Nagasaki.

1947 Hanford experiment on radioiodine in sheep begins.

1947 Work on metabolism of Sr-90 in rhesus monkeys begins (Berkeley).

1947 Publication of Morgan's compendium on tolerance concentrations of radioactive substances -- the computational approach.

1947 Parker describes standard setting and operational limits used in MED operations and important principles.

1947 Higinbotham circuit invented.

1947 Improved linear amplifiers make multichannel analyzers possible for nuclide identification.

1947 Early pulse height analyzer used with radiation detectors. Freundlich, Hincks, and Ozeroff report using a 20 channel analyzer with a proportional counter.

1947 Dynamic condenser electrometer invented by Palevsky, Swank, and Grenchik.

1947 Effects of strontium and plutonium on fetal and infant dogs are reported.

1947 Start of long-term toxicity studies in mice (Argonne) with plutonium, radium, uranium, and fission products.

1947-1950s Drs. treat ringworm of scalp with 400 rad x-ray to cause hair to fall out; later shown to be cause of thyroid tumors (Israel).

1947-1970 Work with radium dial painters and patients resumes at MIT and increases markedly. New population found and added. Osteosarcomas multiply. Carcinoma of sinus appears.

1948 (April - May) Sandstone bomb tests at Eniwetok, 3 tower shots, biggest 49 KT.

1948 (May 14) Four people exposed to fallout of fission products at Eniwetok in the South Pacific. Four employees, who were handling fission samples improperly, received whole-body exposures ranging from 1.7 rem to 17 rem.

1948 Heinz Spiess asked to investigate Ra-224 therapy cases in Germany.

1948 Six patients at U. of Rochester who received uranium for kidney function tests described. Threshold for kidney damage described.

1948 Halogen quenching gases introduced in gas-filled detectors.

1948 Transistor invented by Shockley, Bardeen, and Brattain.

1949 (Mar 1) AEC announces the selection of a site in Idaho for the National Reactor Testing Station.

1949 (May) William Bailey, maker and user of Radithor, dies of bladder cancer.

1949 (Aug 29) USSR explodes first A-bomb at Semipalatinsk, Kazakhstan.

1949 (Sept 7) Accident at Los Alamos Labs 1 person exposed to transuranics.

1949 (Sept 23) Truman announces USSR has tested A-bomb.

1949 (Oct 29) AEC committee headed by Oppenheimer votes against hydrogen bomb. Teller urges construction.

1949 (Dec 2) The Green Run at Hanford reprocesses one ton of irradiated uranium 16 days after irradiation (instead of normal 83-101 days); releases 20,000 curies of xenon-133 and 7,780 curies of iodine-131; plume measures 200 by 40 miles.

1949 First Tri-Partite Conference on Internal Dosimetry (Chalk River, Ontario). Accumulated experience of war years utilized.

1949 NCRP lowers basic "Maximum Permissible Dose" for radiation workers to 0.3 rem/week; risk-benefit philosophy introduced; limits for the general public set at 10% of the occupational limit.

1949 Officials in Mayak Chemical Combine at Chelyabinsk, USSR begin dumping wastes from plutonium production into the Techa River. From 1949 to 1956, 2.75 million curies of radioactivity is dumped into the river without notifying the townspeople downstream. Some exposed to doses as high as 350 rem/yr.

1949 Berkelium discovered by G. T. Seaborg, S. G. Tompson, and A. Ghiorso (United States).

1950 (Jan 21) Truman orders construction of hydrogen bomb.

1950 (Jan)174 Aircraft Factory Kansas, 1 person accidentally exposed to an x-ray device.

1950 (April 11) Kirtland AFB, New Mexico, B-29 crash kills crew of 13 and high explosive of nuclear weapon burns.

1950 (Aug 17) Julius and Ethel Rosenberg indicted in atom spy case.

1950 Second Tri-Partite Conference on Internal Dosimetry (Buckland House, Harwell, U.K.)

1950 Californium discovered by G. T. Seaborg, S. G. Tompson, A. Ghiorso, and K. Street Jr. (United States).

1950 ICRP and ICRU reorganized from pre-war committees and expand scope of interest beyond medicine.

1950 ICRP adopts basic MPC of 0.3 R/week for radiation workers.

1950s Radium beagle studies in Utah and Davis.

1950s AEC develops regulations for individual radionuclides under occupational exposure conditions.

1950s Fallout shelters are built as part of major Civil Defense program.

1950-1954 Work with tritium at Hanford includes checks in man.

1950s-1960s Argonne study of Ottawa and La Salle, Illinois radium dial painters.

1950s-1970 Large scale program at Argonne on toxicity of radium in mice.

1951 (Jan - Feb) Sandstone bomb tests at Nevada Test Site, five air drops; yield range 1.0 - 22 KT. in the Ranger Series

1951 (April - May) Test-shot Greenhouse bomb tests at Eniwetok; four tower shots.

1951 (May 1) Test-shot Dog 19 kT at Nevada Test Site..

1951 (May 8) Test-shot George 225 kT at Nevada Test Site.

1951 (Oct - Nov) Buster-Jangle bomb tests at Nevada Test Site; 7 shots from 0.1 to 31 KT; includes first surface and underground bursts (each 1.2 KT).

1951 (Oct 30) Test-shot Buster Charlie 14 kT at Nevada Test Site.

1951 (Nov 1) Test-shot Buster Dog 21 kT at Nevada Test Site..

1951 (Nov 5) Test-shot Buster Easy 31 kT at Nevada Test Site.

1951 (Dec 20) First electricity is generated from atomic power at EBR-1 Idaho National Engineering Lab, Idaho Falls.

1951 Rocky Flats Nuclear Weapons Facility is constructed 16 mi. from Denver.

1951 Follow-up of Los Alamos plutonium workers begins.

1951 K. Z. Morgan suggests lowering allowable exposure levels of radon.

1951 First organizational recommendations since 1941 for permissible levels of radionuclides, primarily from NCRP.

1951 Raben and Bloembergen introduce liquid scintillation counting for low energy beta minus emitters.

1951 McKay reports using a semiconductor device as an alpha-particle detector.

1952 (April - June) Tumbler-Snapper bomb tests at Nevada Test Site; 8 shots; yields 1 to 31 kT.

1952 (April 1) Test-shot Able 1 kT at Nevada Test Site.

1952 (April 22) Test-shot Charlie 2 31 kT at Nevada Test Site.

1952 (May 25) Test-shot Fox 11 kT at Nevada Test Site.

1952 (June 1) Test-shot George 2 15 kT at Nevada Test Site.

1952 (June 2) Reactor criticality accident at Argonne National Labs, 4 persons exposed. Manual withdrawal of a control rod from a critical assembly caused in accidental supercriticality. The operation being conducted was the comparison of a series of newly-manufactured control rods. The assembly had been operated with the standard control rod. It was then shut down by inserting all control rods and draining the water moderator, a standard safe method of shutting down the assembly when core changes are to be made. The standard rod was removed and the first of a. series of control rods to be tested was inserted. The, reactor was filled with water with the test control rod fully in and the standard type control rods fully inserted. Withdrawal of one of the standard control rods 32 centimeters caused the assembly to become critical and the power was leveled off while the desired measurements were made. The control rod was then reinserted into the original "in" position. With the water still in the assembly, the four members of the crew then went into the assembly room for the purpose of replacing the control rod which they had just tested. The group leader went up on the platform, reached out with his right hand and started to pull out the tested rod. As soon as he had withdrawn it about one foot, the center of the assembly emitted a bluish glow and a large bubble formed. Simultaneously, there was a muffled explosive noise. The group leader let go of the control rod which he was removing and it fell back into position. The crew left the assembly room immediately and went to the control room. Four employees received radiation exposures ranging from 12 to 190 rem.

1952 (June 5) Test-shot How 14 kT at Nevada Test Site.

1952 (July 9) Accidental exposure of 1 person to transuranics at Los Alamos Scientific Labs.

1952 (Oct - Nov) Ivy bomb tests at Pacific Proving Grounds; 2 shots; includes first hydrogen bomb: "Mike".

1952 (Oct 3) Great Britain explodes its first A-bomb (25 KT) in lagoon of Monte Bello Islands off Western Australia.

1952 (Oct 31) US explodes the first hydrogen bomb Test-shot Mike 10.4 MT at Eniwetok.

1952 (Oct) Operations begin at the Savannah River Plant in Aiken, South Carolina, with the startup of the heavy water plant.

1952 (Nov 15) Test-shot King 500 kT at Eniwetok.

1952 (Dec 12) Explosion and meltdown at NRX reactor Chalk River, Ontario, Canada. Future U.S. president Jimmy Carter, thru his involvement in the US Nuclear Submarine program, is one of the volunteer workers who participates in the cleanup, going in until he receives his Maximum Permissible Dose.

1952 Charlie Steen discovers largest underground uranium deposit ever found in U.S. and begins the uranium boom.

1952 Long-term experiments on thousands of mice with Sr/Y (Argonne).

1952 Follow-up on Ra-224 cases begins.

1952 First beagle injected with radioactive material at Utah.

1952 Synthesis of einsteinium discovered in products of first thermonuclear test. Kept secret until 1955.

1952 Marinelli studies transport of radium in lung of man (ANL).

1952 Radiation Research Society formed.

1953 (Jan) Experimental reactor criticality accident in USSR, 2 persons exposed, doses of 300 rem and 450 rem external gamma.

1953 (Mar - June) Upshot-Knothole bomb tests at Nevada Test Site; 11 shots 0.2 - 61 KT; first firing of nuclear warhead from cannon (15 KT) and Shot Harry which leads to contamination of St. George, Utah and the "downwinders".

1953 (Mar 17) Test-shot Annie 16 kT at Nevada Test Site.

1953 (April 25) Test-shot Simon 43 kT at the Nevada Test Site.

1953 (May 19) Test-shot Harry 32 kT at Nevada Test Site.

1953 (May 25) Test-shot Grable 15 kT at Nevada Test Site.

1953 (June 4) Test-shot Climax 61 kT at Nevada Test Site.

1953 (June 19) Rosenbergs executed as spies who gave the plans for the atomic bomb to the USSR.

1953 (Aug 12) USSR explodes its first hydrogen bomb.

1953 (Oct 14 & 26) Operation Totem, British tests, 10 KT and 8 KT explode at Emu Field test site in South Australia. In Operation Hot Box, 3 men fly thru mushroom cloud six minutes after detonation of Totem 1 and receive 10-15 rem.

1953 (Dec 8) Eisenhower delivers "Atoms for Peace" speech to UN General Assembly.

1953 (Dec 23) Oppenheimer loses security clearance due to contact with Communists in the '30s (and opposition to H-bomb.)

1953 International Commission on Radiological Units introduces concept of absorbed dose defining the rad as depositing 100 ergs per gram of any substance.

1953 Synthesis of fermium. Like einsteinium, it is found in hydrogen bomb products and is kept secret until 1955.

1953 Argonne Cancer Research Hospital opens.

1953 Third Tri-Partite Conference on Internal Dosimetry (Arden House, Harriman, NY) sets dose limit of 1.5 rem/yr. to individual members of the general public; 100 pCi/l of air for radon (12 WL months/yr.).

1953 Production of nuclear weapons triggers begins at Rocky Flats, CO.

1953 Melbourne, Australia major overexposure to one individual (dose unknown) to Co-60

1954 (Jan 21) US Navy launches the first nuclear powered submarine, the U.S.S. Nautilus; capabilities include cruising 62,500 miles without refueling.

1954 (Jan 27) Revised Federal radiation protection guidance for workers is published in US.

1954 (Feb - May) Castle bomb tests at Pacific Proving Grounds; 6 shots; includes 15 MT "Bravo".

1954 (Feb 28) Test-shot Bravo 15 MT at Bikini Is.

1954 (March 1) US hydrogen bomb Test-shot (Castle Bravo) over Bikini results in fallout over Marshall Islands, contaminates crew of 23 on Fortunate Dragon 7, 28 US servicemen, and 239 Marshall Islanders.

1954 (April 25) Test-shot Union, 6.9 MT Bikini Island.

1954 (May 29) The Society of Nuclear Medicine holds its first meeting.

1954 (June) First electricity generated from nuclear power in USSR in a five megawatt power station.

1954 (Aug 30) Atomic Energy Act of 1954 passed permits private ownership of nuclear power.

1954 (Sept 6) Ground broken for Shippingport Atomic Power Station (PA).

1954 (Sept 13) 40,000 USSR soldiers participate in wargame where a nuclear bomb is detonated at 1,150 feet in the air. Troops sent immediately into contaminated dust in Totsk, Kazakhstan.

1954 Work on Ra-223, daughter of actinium, and its biological effects (Berkeley, CA).

1954 Kerr-McGee opens uranium mines in Red Rock, Arizona, employing 100 Navajos.

1954 Indications appear that tissue burdens of uranium in man are lower than predicted by models (Eisenbud & Quigley).

1954 Radioactive particles receive attention at Hanford.

1954 Utah conference on plutonium, radium, and mesothorium (2nd Annual).

1954 Start-up of Rocky Flats plant (Colorado).

1954 Mercury, NV An employee unknowingly worked and slept in close proximity to highly contaminated equipment while it was in transport between testing sites. He received a 24 rem whole-body exposure in 24 hours; his total yearly exposure was 27.8 rem.

1954 Mercury, NV While handling 55-gallon drums, whose greasy surfaces had trapped considerable amounts of radioactive fallout, an employee received 13 rem whole-body exposure during one working day. His total yearly exposure was 15.14 rem.

1955 (Jan 10) AEC announces the Power Demonstration Reactor Program under which the AEC and industry would cooperate to build and operate reactors.

1955 (Feb 22) Test-shot Moth 2 kT at Nevada Test Site.

1955 (Feb - May) Teapot bomb tests at Nevada Test Site; 6 shots; yields 1 - 43 kT.

1955 (Mar 1) Test-shot Tesla 7 kT at Nevada Test Site

1955 (Mar 1) 1 person exposed to fission product fallout at Nevada Test Site. A security guard was to accompany the radiation safety monitors into the exclusion area, after a. weapons test and establish surveillance of equipment. The guard had his own vehicle. When he arrived at the place where he was to meet the monitors, the guard found that they had already left and started out after them. Somehow, he lost his way and drove beyond the established safety point. When it became apparent that he could not find the radiation safety monitors, he contacted his headquarters by radio and notified them of his position. He was immediately ordered out of the area. The guard's film badge indicated he had received a dose of 39 rem.

1955 (Mar 12) Test-shot Hornet 4 kT at Nevada Test Site

1955 (Mar 22) Test-shot Bee 8 kT at Nevada Test Site.

1955 (Mar 29) Test-shot Apple 14 kT at Nevada Test Site.

1955 (April 15) Test-shot Met 22 kT at Nevada Test Site.

1955 (May 5) Test-shot Apple II 29 kT at Nevada Test Site.

1955 (May 14) Wigwam bomb test off west coast of US; 1 deep (2000 ft) underwater burst of 30 kT.

1955 (May 17) Fermi and Szilard patent the CP-1 pile.

1955 (June 13) Decision is made to form the Health Physics Society.

1955 (July) Arco, Idaho becomes the first U.S. town to be powered by nuclear energy.

1955 (Aug 8-20) First UN International Conference on Peaceful Uses of Atomic Energy held in Geneva, Switzerland.

1955 (Nov 22) USSR explodes second hydrogen bomb.

1955 (Nov 29) EBR-1 melts half its fuel rods.

1955 (Dec 8) Melbourne, Australia, 3 persons are accidentally exposed to a Cs-137 radiography device.

1955 The Health Physics Society is formed.

1955 Albert Einstein (born 1879) dies.

1955 Formulation of standards for single exposures by Morgan, Snyder, & Ford.

1955 United Nations Scientific Committee (UNSCEAR) organized to gather information, much of it pertinent to standard setting.

1955 Synthesis of mendelevium G. T. Seaborg, S. G. Tompson, A. Ghiorso, and K. Street Jr. (United States).

1955 Hanford, WA Overexposure to Pu-239 (dose unknown)

1956 (Jan 18) Reynolds Electric, Las Vegas, NV, When the prescribed time after a shot had elapsed, four employees, dressed in the proper protective clothing, were recovering samples from a nuclear test area. It had been prearranged to have a. monitor enter the area. in advance of the men; however, they entered the area to redeem the samples without the monitor. The four men received external radiation exposures of 28, 19, 14 and 4 rem, respectively. Upon medical examination, the men showed no signs of ill effects.

1956 (April 30) Los Alamos Scientific Labs accidentally exposes one person to transuranics.

1956 (May - July) Redwing bomb tests at Pacific Proving Grounds; 13 shots; first US airdrop of thermonuclear device (MT range).

1956 (May 16 & June 19) Operation Mosaic, British tests, 15 KT & 98 KT on Monte Bello Islands in West Australia; cloud contaminates mainland on second shot.

1956 (June 6) AEC safety study warns against construction of the Fermi breeder plant.

1956 (June 6) Test-shot Seminole 13.7 kT at Eniwetok.

1956 (June 11) Test-shot Blackfoot 8.5 kT at Eniwetok.

1956 (June 25) Test-shot Dakota 1 MT Bikini Is.

1956 (July 2) Test-shot Mohawk 350 kT at Eniwetok

1956 (July 8) Test-shot Apache 1.9 MT at Eniwetok.

1956 (July 23) Idaho Falls, ID During a shutdown operation for scheduled refueling, six employees were working on the reactor top adjacent to the reactor tank opening, while two men were present as observers and advisors. All were exposed to radiation when a highly radioactive reactor component was placed in a position where it was not adequately shielded because of lowered water level in the reactor tank. The moving of the component and the coincident lowering of the water level were done to facilitate insertion and removal of experiments in the reactor. The eight employees received radiation exposures, ranging from 2.5 rem to 21.5 rem.

1956 (July 27) Broken Arrow 1, Lakenheath AFB, UK. US B-47 bomber catches fire on landing and crashes into nuclear bomb storage igloo. 3 Mark 6 bombs containing 8000 lb. of TNT trigger each threaten to explode. Fire crew heroically pour foam on igloo instead of trying to save four trapped fliers.

1956 (Sept - Oct) Operation Buffalo, British tests, 15 KT & 10 KT tower shots, 3 KT airburst, and 1.5 KT surface detonation at Maralinga, South Australia.

1956 (Oct 17) First full-size nuclear power plant, Windscale, opened by Queen Elizabeth II (Britain).

1956 National Academy of Sciences and ICRP recommend lower basic permissible dose for radiation workers to 5 rad/year.

1956 Indications that uranium may be less toxic to humans than animal experiments predict --Eisenbud.

1956 Early reports of strontium metabolism in man by Comar, Laszlo, & Spencer.

1956 Discovery of nonconservation of parity by Lee and Yang.

1956 Irene Joliot-Curie (born 1897) dies of aplastic anemia.

1957 (Jan 1) US Air Force and AEC pick Lawrence Livermore National Laboratory (California) to develop Pluto, a Supersonic Low-Altitude Missile. Pluto uses a nuclear ramjet to propel itself to Mach 3. Its reactor, Tory, is designed by Ted Merkle. The missile is planned to fly under radar and drop hydrogen bombs on the USSR.

1957 (Mar 29) "Study of Some Physical and Biological Aspects of the Action of High Energy Electrons on Microorganisms." is published by Michael Reese Hospital. The work, (for the U.S. Army Quartermaster Corps, is to "be used in developing the high energy electron beam from the linear accelerator as a tool for the preservation of food by irradiation

1957 (May - Oct) Plumbbob bomb tests at Nevada Test Site; 24 shots; including the highest yield shot fired to date in the continental US ("Hood", 74 KT); first deep (790') underground burst ("Ranier", 1.7 KT).

1957 (May 15) First British hydrogen bomb destroys Christmas Island in South Pacific.

1957 (May 22) Broken Arrow 2, Kirtland AFB, New Mexico; B-36 bomber mistakenly releases 10 MT Mark 17 hydrogen bomb at 1700 feet over University of NM land; makes crater 12 ft deep and 25 ft in diameter; no contamination found.

1957 (May 28) Test-shot Boltzmann 12 kT at Nevada Test Site.

1957 (July 24) Test-shot Kepler 10 kT at Nevada Test Site.

1957 (July 28) C-124 goes down in Atlantic losing two nuclear weapons which are never recovered.

1957 (July) The Sodium Reactor Experiment in Santa Susana, CA. generates the first power from a civilian nuclear reactor.

1957 (Aug 7) Test-shot Stokes 19 kT at Nevada Test Site.

1957 (Aug 18) Test-shot Shasta 17 kT at Nevada Test Site.

1957 (Aug 30) Test-shot Franklin 4.7 kT at Nevada Test Site.

1957 (Aug 31) Test-shot Smokey 44 kT at Nevada test site.

1957 (Sept 1) Eisenhower signs Price-Anderson Amendment to the Atomic Energy Act to limit liability in case of nuclear industry accident.

1957 (Sept 2) Test-shot Galileo 11 kT at Nevada Test Site.

1957 (Sept 11) $1 million fire in Building 771at Rocky Flats, CO blows out all 620 filters and releases unspecified amount of contamination from the 30 - 45 lb. of burning plutonium.

1957 (Sept 14) Test-shot Fizeau 11 kT at Nevada Test Site.

1957 (Sept 16) Test-shot Newton 12 kT at Nevada Test Site.

1957 (Sept 29) Explosion of underground, high-level nuclear waste storage tank at Mayak Chemical Complex, near Chelyabinsk and Kyshtym (USSR) in the Urals vents 2 million curies over 15,000 sq. miles. Population of over 250,000 resettled due to Sr-90 contamination, 10,180 exposed. Possibly the world's worst nuclear accident.

1957 (Sept - Oct) Operation Antler, British tests, 1 KT & 6 KT tower shots, 25 KT air burst.

1957 (Sept) U.S. sets off first underground nuclear test in a mountain tunnel in the remote desert 100 miles from Las Vegas, NV.

1957 (Oct 1) UN establishes the International Atomic Energy Agency (IAEA) in Vienna, Austria.

1957 (Oct 4) Oak Ridge, TN. An employee received an exposure to radiation for less than one minute when he mistakenly entered a room containing tanks of radioactive residues used in processing irradiated fuel elements. The exposure was first discovered when a pocket dosimeter was examined at the end of the day's shift and was confirmed when the employee's film badge was processed. He apparently suffered no ill effects and continued working; however, he was transferred to other duties. Dose was measured at 63 rem.

1957 (Oct 10-12) Fire at Windscale Pile No. 1 (England) releases I-131 over 200 sq. mi. Contaminated milk dumped into Irish Sea.

1957 (Oct 11) Homestead AFB, Fl., B-47 crashes on landing, kills four man crew, high explosives on nuclear weapon explode.

1957 (Dec 2) Shippingport, a PWR/LWBR, goes critical in Shippingport, PA; closed Oct 1982.

1957 NCRP introduces age prorating concept of 5(N-18) for occupational exposure and 0.5 rad/year general public.

1957 American Council of Governmental Industrial Hygienists suggests a single value for air concentration of both soluble and insoluble natural uranium.

1957 US Congressional Joint Committee on Atomic Energy begins series of hearings on radiation hazards, beginning with "The Nature of Radioactive Fallout and Its Effects on Man."

1957 Wash-740 projects damage from maximum credible nuclear accident.

1957 Nobelium discovered at the Nobel Institute of Physics (Sweden).

1958 (Jan 31) Sidi Slimane, French Morocco, US B-47 crashes with one nuclear weapon, radioactive contamination spread to asphalt beneath plane wreckage.

1958 (Mar 11) Broken Arrow 3, Florence, SC, B-47 drops bomb from 14000 ft on garden of Walter Gregg in Mars Bluff, SC makes crater 35 ft deep and 75 ft across; chemical trigger designed to set off TNT explodes spreading plutonium contamination.

1958 (April - Aug) Hardtack-Phase I bomb tests at Eniwetok Proving Grounds; 31 shots; including 2 rockets detonated at high altitudes (up to 252,000 feet).

1958 (May 5) Test-shot Cactus 18 kT Eniwetok Is.

1958 (May 22) Construction begins on the world's first nuclear powered merchant ship, N. S. Savannah, in Camden, NJ. Ship is launched July 21, 1959.

1958 (May 23) NRU experimental reactor at Chalk River (Canada) goes out of control and releases radioactivity.

1958 (June 8) Test-shot Umbrella 9 kT at Eniwetok

1958 (June 16) Oak Ridge National Labs, 8 persons exposed at the Y-12 site during a chemical operations criticality accident. A nuclear accident occurred in a 55-gallon stainless steel drum in a processing area in which enriched uranium is recovered from various materials by chemical methods in a complex of equipment. This recovery process was being remodeled at the time of the accident. The incident occurred while they were draining material thought to be water from safe 5-inch storage pipes into an unsafe drum. Eight employees were in the vicinity of the drum carrying out routine plant operations and maintenance. A chemical operator was participating in the leak testing which inadvertently set off the reaction. He was within three to six feet of the drum, while the other seven employees were from 15 to 50 feet away. Using special post hoc methods for determining the neutron and gamma exposures of the employees involved, it was estimated that the eight men received: 461 rem, 428 rem, 413 rem, 341 rem, 298 rem, 86 rem, 86 rem, and 29 rem. Area contamination was slight, with decontamination costs amounting to less than $1,000.

1958 (June 28) Test-shot Oak 8.9 MT at Eniwetok

1958 (June 30) North American Aviation L 47 homogeneous reactor, 5 Wt, in Canoga Park, CA, is closed.

1958 (June) Alice Stewart publishes first major findings on carcinogenic effect of diagnostic radiation on children.

1958 (Aug - Sept) Argus Project; detonation of 3 low-yield nuclear devices in outer space.

1958 (Sept) Troitsk A, a LGR, goes on-line in Troitsk, Chelyabinsk, RSFSR (USSR); closed 1989.

1958 (Sept - Oct) Hardtack-Phase II at Nevada Test Site; 19 shots; including underground tests (100' to 850') and some shots dropped from balloons

1958 (Oct 15) Vinca Yugoslavia 6 persons, experimental reactor criticality accident (est. doses: 436 rad, 414 rad, 426 rad, 419 rad, 323 rad, 207 rad ).

1958 (Oct 22) Test-shot Socorro 6 kT at Nevada Test Site.

1958 (Oct 30) Test-shot Santa Fe 1.3 kT at Nevada Test Site.

1958 (Nov 4) Dyess AFB, Texas, B-47 catches fire on take-off; nuclear weapon's high explosive detonates, blasting crater 35 ft in diameter and 6 ft deep; nuclear materials recovered near crash site; one killed in crash.

1958 (Nov 18) Heat Transfer Reactor Experiment Facility, National Reactor Testing Station in Idaho, suffers extensive fuel damage and releases radioactive material.

1958 (Nov 26) Chennault AFB, Lake Charles, LA, B-47 catches fire on the ground, one nuclear weapon destroyed, contaminates wreckage.

1958 (Dec 30) Los Alamos Scientific Lab, 3 persons exposed during a chemical operations criticality accident. After placing emulsion in a tank, the operator was believed to have added a dilute plutonium solution from a second tank. Solids containing plutonium were probably washed from the bottom of the second tank with nitric acid and the resultant mixture of nitric acid and plutonium-bearing solids added to the tank containing the emulsion. Shortly after starting the stirrer motor to initiate an expected mild non-nuclear reaction between the emulsion and the acid, the operator observed a "blue flash", also observed by an employee in an adjoining room. The employee died 35 hours later from the effects of a radiation exposure tentatively estimated at 12,000 rem (±50%). Two other employees received radiation exposures of 134 rem and 53 rem, respectively. Property damage was reported as negligible.

1958 United Nations Scientific Committee on the Effects of Atomic Radiation publishes study of exposure sources and biological hazards (first UNSCEAR Report).

1958 Society of Nuclear Medicine formed.

1958 Frederic Joliot-Curie (born 1900) dies.

1958 Construction begins on Dresden #1.

1958 Reprocessing plant criticality at Los Alamos, NM kills 1.

1958 Bureau of Radiological Health organized within US Public Health Service.

1958 Stannard proposes that lung be regarded as a moderately radiosensitive organ.

1958 Discovery of the Van Allen radiation belts.

1958 Synthesis of nobelium.

1959 (Jan 6) Livermore, Ca A physicist was exposed while a series of adjustments were being made on beam-defining plates in a new electron linear accelerator. Radiation surveys were made with negative results when personnel entered the cell after the first three adjustment runs. No survey was made after the fourth and fifth runs. A survey made after the sixth run showed a 1,000 rem/hr level. During all entries to the cell, the key which was designed to lock all controls in the "OFF" position was removed from the control panel. It was determined that the film badges had been exposed to about 200 Kev energy gamma radiation. An exposure dose of 41 rem was assigned to physicist "A". This dose was received in a period of about one minute, which was the established time he worked alone on plates 3 and 4 and entered the cell to measure very high radiation levels. The next highest reading of 400 millirem was received by physicist "B". All others received less than 50 millirem.

1959 (Feb 17) High levels of Sr-90 reported in US milk and in children's bones.

1959 (Apr) Marcoule G2, a GCR, goes on-line in Marcoule, Gard (France); closed Feb 1980.

1959 (July 6) Barksdale AFB, Louisiana, C-124 crashes on take-off, catches fire and destroys nuclear weapon, spreading contamination below the weapon.

1959 (July 21) Nuclear merchant vessel, Savannah, is launched.

1959 (July 26) AEC's Sodium Reactor Experiment reactor, Santa Barbara, CA, 10 of 43 fuel assemblies damaged due to lack of heat transfer, releases contamination.

1959 (Aug 18) Federal Radiation Council (FRC) formed to advise the US President about radiation matters, especially standards. Series of reports issued.

1959 (Oct) Dresden-1 Nuclear Power Station in Illinois achieves a self-sustaining nuclear reaction. It is the first US nuclear power plant built entirely without government funding.

1959 (Nov) Chemical explosion disperses 15 g of plutonium at Oak Ridge, TN.

1959 (Dec) Troitsk B, an LGR, goes on-line in Troitsk, Chelyabinsk (USSR); closed 1989.

1959 Leaking waste drums discovered at Rocky Flats, CO. Radioactive oils from drums flow into soil, contaminating farmlands east of plant.

1959 ICRP 1 published (superseded by ICRP 26); recommends limitation of genetically significant dose to population.

1959 Large feeding experiment with Sr-90 begins with miniature swine at Hanford.

1959 Tri-State Leukemia Survey begun in NY, Minnesota, & Maryland.

1959 Report of Committees 2 of NCRP and ICRP on occupational limits for exposure to radionuclides. Utilizes dual system; uses effects directly for radium and bases other bone seekers on it; uses the computational approach for all others using external radiation effects as basis.

1959 Johannessburg, South Africa Co-60 overexposure (dose unknown).

1960 (Feb 13) France explodes its first A-bomb.

1960 (Mar 8) Niagara Falls, NY (Lockport Air Force Base), 9 persons exposed to radiation from a radar klystron tube. 6 over 25 rem (up to 1200 rad localized).

1960 (Mar 15) Gen. Dynamics CIRGA Zirconium Hydride Mod., 25 Wt, in San Diego, CA is closed.

1960 (Mar 29) U. of Wisconsin, 12 people are accidentally exposed to radiation from a Co-60 source. One overexposure of up to 300 rad.

1960 (April 3) Waltz Mill, test reactor outside Pittsburgh, PA melts one fuel element.

1960 (May) Marcoule G3, a GCR, goes on-line in Marcoule, Gard (France); closed July 1984.

1960 (June 7-8) Jackson, New Jersey, BOMARC missile catches fire, unknown amount of plutonium released to atmosphere.

1960 (June 8) 19-yr. old commits suicide with 10 Ci. Cs-137 source; exposure time 20 hr approximately 1500 rad.; death 18 days later (USSR).

1960 (July) Dresden #1 goes online, first BWR, 700 MWt, manufactured by GE, in Morris, Ill; closed Oct 31,1978.

1960 (Sept 1) Lockheed pool-type reactor, 10 Wt, in Dawson Co., Georgia, is closed.

1960 (Oct 4) Two employees were following through the routine involved in the calibration of photocell detectors. The detectors were placed in the radiation beam area, 30" in front of the 340-curie cobalt 60 source unit. Currents were being recorded for each detector with the source exposed. Three detectors had previously been calibrated; the fourth was placed in position; both employees returned to the console; the source was exposed and the current output of the detector was recorded. After recording the current value, employee "A" noted that the warning lights were out and assumed that the source was no longer exposed. He approached the detector located in front of the source, without making a precautionary radiation survey, and started making mechanical adjustments on the photodiode. Employee "B" followed "A" and aided him in the adjustments. "A" received a, total-body dose of 18 rem as determined by film badge reading. "B" received a total whole-body dose of 5 rem.

1960 (Nov 8) Sandia National Lab, NM 2 persons accidentally exposed to radiation from a Van de Graaf accelerator.

1960 (Nov 28) Six men soaked with reactor coolant from USS Nautilus docked at Portsmouth, NH; dosimeters and contaminated clothing thrown away.

1960 (Nov 9) Patient swallows 2.03 millicuries of radium-226; calcium DTPA given as therapy, dies Aug 1965 from permanent blood changes (USSR).

1960 Yankee Rowe Nuclear Power Station, 600 MWt, PWR, goes on line in Rowe, Mass. closed Oct 1, 1991.

1960 Miniature swine at Hanford enter radioiodine experiment.

1960 First series of BEAR reports issued by NAS-NRC. Does not address standards directly but contains much pertinent information.

1960 ICRP 3 "Report of Committee III on Protection Against X-rays up to Energies of 3 MeV and Beta- and Gamma-rays from Sealed Sources" published.

1960 US Congressional Joint Committee on Atomic Energy holds hearings on "Radiation Protection Criteria and Standards: Their Basis and Use."

1960 American Association of Physicists in Medicine formed.

1960 American Board of Health Physics begins certification of health physicists.

1960 First successful laser.

1960s Metabolism of americium and radiocalcium in rat (Durbin at Berkeley).

1960s Large effort at Oak Ridge on trace elements in human tissue.

1960s Beginning of population radiation exposure standards.

1960s AEC develops elaborate code of Federal Regulations for radionuclide exposure (10CFR20). Patterned after 1959 ICRP/NCRP reports but adds population exposure limits by use of a scaling factor.

1960-1961 First two reports from Federal Radiation Council on basic radiation protection guides. Introduces formally the concept of balancing risks and benefits.

1961 (Jan 3) Prompt criticality accident at SL-1 US Army reactor in Idaho Falls kills three. Recovery efforts expose 47 persons.

1961 (Jan 29) Broken Arrow 4, Goldsboro, NC B-52 crashes, 24 MT bomb is one interlock away from detonating, hole 50 ft deep and 3 acres in area excavated to look for portion of one weapon, 4 million cu. ft. of earth removed.

1961 (May 11) Mound EG&G Miamisburg, OH, 2 persons involved in plutonium exposure.

1961 (June) Walter Reuther releases study of forty reactor accidents, arguing against construction of Fermi breeder.

1961 (June 12) US Supreme Court gives Fermi breeder go ahead to begin construction.

1961 (June 18) Reactor LOCA on the first USSR nuclear missile submarine, the K-19. Fourteen crew members allegedly die from radiation exposure rigging a provisional cooling system using a reserve tank and pipes cut off one of the torpedoes. The welding took 90 minutes. Capt. Nikolai Zateyev reported that "the ones who got radiation doses began to swell visibly. Their faces grew red. After two hours, watery discharges came from the roots of their hair. Soon it became frightening to look at their eyes and swollen lips. They were completely disfigured. Hardly able to move their tongues, they complained of pain in the entire body." Over thirty sailors receive doses from 100 to 5000 rem. Eight officers and sailors died within days, six more died within the next several years.

1961 (June 22) Nuclear Dev. Corp. of America Crit. Ex., 100 Wt, in Pawling, NY, is closed.

1961 (Sept 1) USSR resumes nuclear testing.

1961 (Sept 15) US resumes underground testing.

1961 (Sept) President Kennedy advises Americans to build bomb shelters.

1961 (Oct 3) USSR explodes a 58 megaton hydrogen bomb in the air over Novaya Zemla. Largest weapon ever exploded in history.

1961 (Oct 20) Ohio Rad Lab, Miamisburg, OH, 4 persons involved in polonium exposure.

1961 (Oct 21) Oak Ridge National Labs, TN, accident at X-10 site exposes 1 person to fission products.

1961 (Nov 25) US Navy commissions world's largest ship, the U.S.S. Enterprise, a nuclear powered aircraft carrier.

1961 Switzerland a tritium exposure of three individuals up to 300 rem leads to one fatality.

1961 Plymouth, UK overexposure to X-rays for 11 persons.

1961 Fontenay-aux-Roses, France overexposure of one person to plutonium.

1961 Atmospheric testing of nuclear weapons is resumed as well; over 100 detonations occurred before the treaty was signed

1961 First documented cases of dumping of radioactive waste into the Barents Sea (north of Finland) by USSR navy vessels.

1961 Synthesis of lawrencium by A.H. Ghiorso, T. Sikkeland, A. E. Larsh, R. M. Latimer (United States).

1961 Federal Regulations adopted in Title 10 Code of Federal Regulations, Part 20.

1961 20 aged volunteers receive injections with radium in and thorium in Boston, MA. Potential doses well above occupational limits. No follow-up done.

1962 (Feb 8) Kentucky becomes first agreement state in US.

1962 (Apr 7) Hanford, Washington, 22 persons accidentally exposed in a chemical operations criticality. An unplanned nuclear excursion occurred in a plutonium processing facility due to the inadvertent accumulation of approximately 1500 grams of plutonium in 45-50 liters of dilute nitric acid solution in a 69-liter glass transfer tank. The sequence of events which led to the accumulation of the plutonium in the tank cannot be stated positively. However, it is believed that, when a tank valve was opened, the solution from another vessel overflowed to a sump and was drawn into the transfer tank through a temporary line between this tank and the sump. When the excursion occurred, radiation and evacuation alarms sounded. All but three employees left the building immediately, according to well-prepared and -rehearsed evacuation plans. Fortunately, they were not in close proximity to the involved system nor in a high radiation field. Of the 22 persons in the building at the time, only four employees, those who were in the room with the system, were hospitalized for observation. Three of them were the system operators, who were in close proximity to the excursion, and who received estimated radiation doses of 110, 43 and 19 rem. None, of them showed symptoms definitely referable to their radiation exposures. The fourth was sent to the hospital only because he was in the room at the time of the incident. Some fission product activity, airborne via, the vent system and the exhaust stack, was detected in the atmosphere for a brief period after the accident. The physical damage amounted to less than $1,000.

1962 (April 27) Test-shot Aztec 20 kT - 1 MT Christmas Is.

1962 (May 2) Test-shot Arkansas 1 MT Christmas Is.

1962 (May 8) Test shot Yukon 1 MT Christmas Is.

1962 (May 14) Test-shot Swanee 20 kT - 1 MT, Christmas Is.

1962 (May 19) Test-shot Chetko 20 kT - 1 MT Christmas Is.

1962 (May 27) Test-shot Nambe 20 kT- 1 MT, Christmas Is.

1962 (June 9) Test-shot Trukee 20 kT- 1 MT, Christmas Is.

1962 (June 10) Test-shot Yeso >1MT Christmas Is.

1962 (June 10) Test-shot Sunset 20 kT - 1 MT, Christmas Is.

1962 (June 19) Test-shot Starfish, 1.4 MT explosion 400 km. above mid-Pacific, launched from US Johnston Island.

1962 (June 27) Test-shot Bighorn > 1 MT at Christmas Is.

1962 (June 30) Test-shot Bluestone > 1 MT at Christmas Is.

1962 (July 9) Test-shot Starfish 1 MT over Johnston Is.

1962 (July 25) Test-shot Bluefish Prime; missile blows up on pad, warhead detonated by radio spreading contamination over the pad.

1962 (July 25) Mayaguez, PR, Seven employees were accidentally exposed to radiation from irradiated fuel elements when a crane operator mistakenly thought he had been given the all-clear signal to move a rack of hot fuel elements into a position against the aluminum window which separates the exposure room from the reactor pool. The room was to be vacated and the shield door closed before positioning the fuel elements against the window. The gamma room door could not be seen from the crane operator's position. When the crane operator began moving the fuel elements into the window position, the 10-millirem monitor near the gamma room door tripped an alarm. The reactor supervisor immediately ordered the fuel elements moved away from the window, terminating the incident. The estimated exposure time of the individuals was 1 1/4 seconds. The seven employees' exposures were 100 rem, 58 rem, 24 rem, 18 rem, 18 rem, 8 rem, and 4 rem. There were no radiation injuries as a result of the accident

1962 (Oct 7) Antarctica, Nukey Poo reactor has hydrogen fire in containment.

1962 (Oct 18) Test-shot Chama >1 MT Johnston Is.

1962 (Oct 26) Test-shot Bluegill <1 MT over Johnston Is.

1962 (Nov 1) Test-shot Kingfish < 1 MT over Johnston Is.

1962 (Nov 20) AEC submits a "Report to the President on Civilian Nuclear Power."

1962 (Nov) Berkeley 1, a GCR, goes on-line in Berkeley, Gloucester (Britain); closed Mar 1989.

1962 (Nov) Berkeley 2, a GCR, goes on-line in Berkeley, Gloucester (Britain); closed Oct 1988.

1962 Mexico City, Mexico Overexposure of five to Co-60 capsule leads to deaths of four.

1962 Moscow, USSR overexposure of one person to 380 rad, non-uniform.

1962 FRC Report No. 3 on the health implications of fallout.

1962 Congressional hearings on fallout.

1962 Neils Bohr (born 1885) dies.

1963 (Jan 11) Sanlian, PR China, 6 persons are exposed to a Co-60 source in home (5-9 days) acute radiation syndrome , deaths of two in 11 to 12 days despite bone marrow transplant, amputation of LT. leg of one survivor 5 years post accident.

1963 (Jan) Indian Point 1, a 615 MWt PWR, goes on-line in Buchanan, NY; closed Oct 31,1974.

1963 (Apr 10) Nuclear submarine USS Thresher sinks in North Atlantic.

1963 (Apr 24) Westinghouse CVTR Mockup, Heavy Water, 3 KWt, in Waltz Mill, PA is closed.

1963 (May 16) Richland, WA Construction employees, who wore no dosimeters, were inadvertently exposed to a lost 27-curie iridium 192 radiography source during the construction of a new production reactor. Exposures were estimated based upon radiation surveys and interviews with the personnel involved. The exposures ranged from 3.9 rem to 15.2 rem.

1963 (June 13) Construction begins at first commercial reprocessing facility, West Valley.

1963 (July 1) Oak Ridge Research Reactor, Oak Ridge (Tenn.) melts part of an element releasing 1000 curies of fission products.

1963 (Aug 5) US and USSR sign Limited Test Ban Treaty, which prohibits underwater, atmospheric, and outer space nuclear tests. More than 100 countries eventually ratify the treaty.

1963 (Aug) Humboldt Bay 3, a BWR, goes on-line in Eureka, CA; closed July 2, 1976.

1963 (Nov 13) Medina Base, San Antonio (TX), 123,000 lb. of high explosives on nuclear weapons catch fire.

1963 (Nov) Hallam, a LMGMR, goes on-line in Hallam, Nebraska; closed Sept 1964.

1963 (Dec 9) Vallecitos, a GE BWR, 50 MWt, in Alameda County, CA, closed.

1963 FRC Report No. 4 on estimates and evaluation of fallout in the United States through 1962.

1963 Saclay, France overexposure of 2 to an electron beam doses unknown.

1963 Second Congressional hearing including Radiation Standards and fallo