LAS CRUCES, N.M. (AP) — Dona Ana County and the city of Las Cruces have filed a federal lawsuit seeking damages over contaminated groundwater. In the suit filed Wednesday in U.S. District Court, the city and county say the Department of Defense released hazardous substances during operations at the former National Guard Armory in Las Cruces. The suit says that created a plume of contaminated groundwater about 1.8 miles long and a half-mile wide. The Environmental Protection Agency has designated the area as a federal Superfund site. Las Cruces and the county allege in the lawsuit that the federal government is liable for the contamination. They seek an order compelling the government to assist with ongoing costs of cleanup as well as to recover costs already incurred to build and operate a water treatment plant.