KERMIT, Texas — The U.S. Environmental Protection Agency has given a West Texas site a federal Superfund designation marking it as one of the most hazardous waste sites in the country.

The EPA said in a statement Monday that a portion of the Santa Rosa Aquifer in Kermit has been added to the Superfund program’s National Priorities List.

The aquifer in the city west of Odessa has a contaminated groundwater plume a mile long and 1.5 miles wide.

Local officials first detected trichloroethene, an industrial solvent, in 1990. Tetrachloroethene, widely used to dry-clean fabrics, was detected in 2000.

Federal authorities claim the source of the contamination is not known.

Kermit treats the drinking water prior to releasing it to more than 5,700 customers.

There are more than 1,300 Superfund sites in the country.