By MATTHEW BROWN
BILLINGS, Mont. (AP) — A conservation group has filed a lawsuit against U.S. environmental officials for alleged failure to intervene after Montana rolled back longstanding water pollution rules. The Upper Missouri Waterkeeper group says new rules proposed by the Montana Department of Environmental Quality will let more nutrient pollution into the state’s streams, rivers and other waterways. The lawsuit is against the U.S. Environmental Protection Agency, which has oversight of the state’s pollution rules. Nutrient pollution comes from farm fertilizer, treated sewage waste, industrial plants and numerous other sources. It can be harmful to fish and human health by encouraging the growth of algae that are sometimes toxic. An EPA spokesperson declined comment.