One of the nation's six original low-level radioactive waste sites, Sheffield was opened in 1967, was filled to permitted capacity in 1978, and was subsequently closed. For much of its life it was operated by US Ecology, a division of American Ecology, which also operated the first commercial radioactive waste site in Beatty, Nevada. It has been sued by the state of Illinois for contaminating a nearby lake with radioactivity. Though no longer accepting waste, this site will continue to be radioactive indefinitely and will be off-limits and monitored. It is located next to a former chemical waste site, and is overgrown and in a farming community. There are less than six operating commercial radioactive waste sites in the country, which accept only "low level" waste, such as contaminated laboratory material from medical facilities. High level radioactive waste is managed by the government and the commercial power plants that produce it.