Wichita ? Residents of the southeast Kansas town of Treece face “a unique and urgent threat from the legacy of pollution” and should be relocated, the Environmental Protection Agency said Thursday.

EPA officials made their determination public shortly after Congress approved legislation giving the agency authority to buy out the town.

An amendment to that effect was included in the fiscal 2010 Interior Appropriations Conference Report that was approved by both chambers Thursday. The amendment was introduced by Sens. Pat Roberts and Sam Brownback of Kansas and James Inhofe of Oklahoma.

President Barack Obama is expected to sign the legislation by Saturday.

“EPA has determined that relocation is the primary option to address the concerns of Treece residents — just as it was in neighboring Picher, Okla.,” EPA Administrator Lisa Jackson said in a written statement.

About 70 families live in Treece, where zinc and lead were mined for decades. Many residents are hoping for a government buyout, saying remnants of the old mining operations make it impossible to sell their homes.

Treece Mayor Bill Blunk called it a victory. He said the next step will be the actual buyout, which he anticipates will take 16 to 18 months to complete once a committee is formed and appraisals completed. He praised lawmakers, particularly Roberts, for making it happen.

“They did exceptional work,” Blunk said in a phone interview from Treece. “Sen. Roberts would not let it rest until he finally turned some heads his way to get the things he wanted.”

At Roberts’ urging, the EPA sent top officials to Treece in August to tour the town and talk to residents. At the request of residents, the agency began testing blood lead levels and air quality.

“Once they saw firsthand exactly the danger we faced on a daily basis, they understood,” said Blunk, who has lived in Treece since 1992.

“I applaud the EPA for going the extra mile, sending representatives to the area to listen to residents firsthand, and then understanding their special hardships,” Roberts said in a news release. “Together, I think we can now give these folks a little hope.”

Pam Pruitt, the city clerk, said Roberts called Thursday to give residents the news.

“Everybody is real excited that we are closer, just a little step closer,” Pruitt said. “This answer today kind of cemented it for them. This is really going to happen.”