BILLINGS, Mont. (AP) — A fugitive who escaped custody in Wyoming four years ago has been added to a list of U.S. environmental crimes fugitives and is being sought by investigators for illegally dumping radioactive oilfield waste in North Dakota in incidents dating back to 2011, authorities said Tuesday.

James Kenneth Ward, 55, is considered violent and dangerous and should not be approached, the U.S. Environmental Protection Agency's Criminal Investigation Division said in a statement.

Prosecutors said Ward beginning in 2011 illegally disposed of hundreds of pieces of radioactive oil field wa...