What you need to know about Hanford
The nuclear weapons production that began at Hanford in the 1940s generated substantial amounts of radioactive and chemical wastes, contaminated land and groundwater, and created a lasting legacy of contaminated facilities. Since the signing of the Tri-Party Agreement in 1989, Ecology, EPA, and Energy have worked to clean up, treat, and dispose of this legacy to reduce the threats it poses. Substantial progress has been made, and substantial work remains.
During World War II, the government wanted a large buffer zone around its nuclear production facilities for secrecy and public safety. The current site is about 580 square miles and most areas are still not accessible to the public.