| 1895 | Roentgen discovers xrays. |
| 1896 |
First diagnostic xray in U.S. |
| 1898 | Marie & Pierre Curie coin word "radioactivity." |
| 1903 | Marie and Pierre Curie awarded the Nobel Prize for Physics. |
| 1905 | Albert Einstein develops theory about the relationship of mass and energy. |
| 1910 | Curie unit defined as activity of 1 gram of radium. |
| 1915 | The British Roentgen Society adopted a resolution to protect people from overexposure to xrays. |
| 1922 | Many American organizations adopted the British protection rules. |
| 1925-1929 | The saga of radium dial painters unfolds. |
| 1928 |
Organization of U.S. Advisory Committee on xray and Radium Protection
(predecessor of National Council on Radiation Protection). |
| 1939 | Enrico Fermi patents first reactor (conceptual plans). |
| 1942 | The Manhattan Project is formed to secretly build the atomic bomb before the Germans. |
| 1942 | Enrico Fermi demonstrates the first self-sustaining nuclear chain reaction in a lab at the University of Chicago. |
| 1946 | Atomic Energy Act is passed; establishes Atomic Energy Commission. |
| 1946 | The U.S. Advisory Committee was reorganized and renamed the National Committee on Radiation Protection and operating out of the Bureau of Standards. |
| 1951 | First electricity is generated from atomic power at EBR-1 Idaho National Engineering Lab, Idaho Falls. |
| 1954 | Atomic Energy Act of 1954 is passed to promote the peaceful uses of nuclear energy through private enterprises and to implement President Eisenhower's Atoms for Peace Program. |
| 1954 | The first nuclear submarine, U.S.S. Nautilus, is launched. |
| 1955 |
Arco, Idaho, becomes the first U.S. town to be powered by nuclear energy. |
| 1957 | The first U.S. large-scale nuclear power plant begins operating in Shipingport, Pennsylvania. |
| 1957 | United Nations establishes the International Atomic Energy Agency (IAEA). |
| 1958 |
Bureau of Radiological Health organized within U.S. Public Health Service. |
| 1959 |
Federal Radiation Council (FRC) formed to advise the U.S. President about
radiation matters, especially standards. |
| 1962 | The first commercial low-level waste disposal site was established in Beatty, Nevada. |
| 1968 | Nuclear Nonproliferation Treaty calling for halting the spread of nuclear weapons capabilities is signed. |
| 1970 | U.S. Environmental Protection Agency is formed. Responsibilities include radiation protection. |
| 1970 |
National Environmental Policy Act is signed requiring the federal government
to review the environmental impact of any action — such as construction
of a facility — that might significantly affect the environment. |
| 1971 | Six commercial low-level waste sites operating. |
| 1972 |
Computer axial tomography, commonly known as CAT scanning, is introduced.
A CAT scan combines many high-definition cross-sectional xrays to produce
a two-dimensional image of a patient's anatomy. |
| 1972 |
AEC reveals that since 1946 radioactive waste was dumped off shore of
U.S. coast; biggest dumps near San Francisco, CA, 47,500 55-gallon drums. |
| 1974 | Atomic Energy Commission is abolished and the Nuclear Regulatory Commission and the Energy Research and Development Administration are established. |
| 1975 |
West Valley, New York, low-level waste site closed after water overflowed
from two of its burial trenches. |
| 1976 | The Resource Conservation and Recovery Act (RCRA) is passed to protect human health and the environment from the potential hazards of waste disposal. |
| 1977 | The U.S. Department of Energy replaces the Energy Research and Development Administration. |
| 1977 |
Maxey Flats, Kentucky, low-level waste site closed after some radioactive
materials migrated from the site and the state imposed additional surcharges
making disposal uneconomical. |
| 1978 |
Sheffield, Illinois, low-level waste site closed after reaching capacity. |
| 1979 |
Three Mile Island (Middletown, PA) nuclear power plant suffers hydrogen
explosions and a partial core meltdown. |
| 1979 |
Beaty, Nevada, and Richland, Washington, low-level waste sites closed
temporarily because damaged and leaking nuclear waste containers were being
delivered. |
| 1980 | The Low-Level Radioactive Waste Policy Act is passed, making states responsible for the disposal of their own low-level nuclear waste, such as from the hospitals and industry. |
| 1980 | The Comprehensive Environmental Response, Compensation, and Liability Act (also known as Superfund) is passed in response to the discovery in the late 1970s of a large number of abandoned, leaking hazardous waste dumps. |
| 1983 | The Nuclear Waste Policy Act of 1982 is signed, authorizing the development of a high-level nuclear waste repository. |
| 1985 |
Because no low-level waste state compacts had yet been ratified or sites
selected, Congress amended the act to create siting milestones, deadlines
for compliance, and penalties for failure to meet the deadlines. It provided
that on January 1, 1993, the three states with sites (Washington, South
Carolina, and Nevada) could refuse to accept low-level waste generated outside
their borders by states that are not in their respective compacts. |
| 1986 | Chernobyl Nuclear Reactor meltdown and fire occur in the Soviet Union. Much radioactive material is released. |
| 1987 |
Nuclear Waste Policy Amendments Act designates Yucca Mountain, Nevada,
for scientific investigation as only candidate site for the U.S.'s first
geological repository for high-level radioactive waste and spent nuclear
fuel. |
| 1989 | DOE changes its focus from nuclear materials production to environmental cleanup by forming the Office of Environmental Restoration and Waste Management. |
| 1991 |
The United States and Soviet Union sign historic agreement to cut back
on long-range nuclear weapons by more than 30 percent over the next seven
years. |
| 1992 | The Waste Isolation Pilot Plant (WIPP) Land Withdrawal Act withdraws public lands for WIPP, a test repository for transuranic nuclear waste located in a salt deposit deep under the desert. |
| 1993 | The Beatty, Nevada, low-level waste site closed to low-level waste. |
| 1996 | The United Nations approves the Comprehensive Test Ban Treaty which bans nuclear test explosions. |
| 1999 | An accident at the uranium processing plant at Tokaimura, Japan, exposed fifty-five workers to radiation. One worker later dies. |
| 1999 | The Waste Isolation Pilot Plant began receiving shipments of transuranic waste. |
