KETCHUM, Idaho (AP) — Idaho officials plan to put in a second plug at a leaking central Idaho mine opening to prevent the potential release of millions of gallons of toxic waste near the resort towns of Ketchum and Sun Valley.

The Idaho Department of Environmental Quality tells the Idaho Mountain Express that 200 million gallons of toxic mine drainage is pooled behind a plug installed in 2003 at Triumph Mine. Idaho officials say the 2015 Gold King Mine disaster in Colorado where 3 million gallons of toxic mine waste escaped into the Animas River is something they want to prevent in Idaho.

Idaho is doing remediation work with supervision from the U.S. Environmental Protection Agency. Estimated cost is $16 million. Work is scheduled to begin in the next several weeks.