Private investigators will spend the next three or four years analyzing the area and quantifying what and how much dangerous material needs to be taken care of.

Sen. Jon Tester, D-Mont., was a long-time advocate of getting Superfund listing for the Columbia Falls property. On Wednesday, he praised the announcement and criticized plant owner Glencore AG for delaying the process.

“Glencore can no longer try and turn their back on families in Columbia Falls,” Tester wrote in an email. “This decision guarantees that after seven years of broken promises and stonewalling, Glencore will finally be held accountable for the cleanup of CFAC. Today is a step in the right direction and I will continue to work with folks in Columbia Falls so we can strengthen the local economy, revitalize this site, and create jobs.”

Former CFAC workers Keith Haverfield and Mike Shepherd also backed the move.

“I am for CFAC becoming a Superfund site because after the 36-plus years working there, I saw a lot of materials dumped and buried on the site,” Haverfield said in a statement provided by Tester. “The site needs to be cleaned up properly and professionally. I also believe that Glencore should be responsible for the costs because they knew what they were getting from day one when purchasing the plant.”