The Hanford Nuclear Reservation in southeastern Washington state was used in making plutonium for one of the nuclear bombs used on Japan in WWII. As with other nuclear facilities, releases of radioactive elements into the surrounding environment occured. In a project dubbed Green Run, the facility also tested the effects of radiation on humans by deliberately releasing radioactive elements into the local environment. Apparently, it was done to test the ability of military equipment to detect Soviet plutonium facilities. The Washington State Department of Health has a lot of good background information on the facility.
There are many nuclear facilities around the United States that are military and non-military use. Countless reports of contamination and accidents have shown that nuclear power and weapons production are not safe. Now the nuclear power industry is coming back as an alternative source of power generation. Nuclear weapons are not going anywhere as more and more countries seem to be developing them. Somebody has to take the first step in stopping nuclear power development and the non-proliferation treaties need greater enforcement. It took 40 years for the people near Hanford to find out what was happening. What about other countries that do not have Freedom of Information requests or corrupt governments? We may never find out what is happening half way around the world and could contaminate the entire planet until it is too late.