The Environmental Protection Agency proposes adding a U.S. Magnesium site in Tooele County to the federal Superfund list.
The agency announced Wednesday that the public has 60 days to comment on the proposal.
If the proposal goes through, the 4,525 acres on the southwest edge of the Great Salt Lake would be added to the list of the nation's most contaminated places.
The listing would make cleanup of the site a national priority and allow the EPA and the Utah Department of Environmental Quality to oversee the work.
Company officials have said EPA isn't following procedures and isn't correctly reading science or the law.