The U.S. Navy regularly tests one of its weapons by firing radioactive ammunition into prime fishing waters off the coast of Washington state, a practice that fishers, scientists, and activists say could be harmful to human and environmental health. The weapon, known as the Phalanx or the Close In Weapons System, fires up to 4,500 rounds per minute of depleted uranium (DU), a highly dense metal that remains radioactive for around 4.5 billion years. The Navy insists that DU poses no threat to its crew members or to Washington’s coastal environment. No major studies have been done on the effects of the DU-containing weapons on the ocean environment, but the use of DU in land combat has led to radiation releases and the production of toxic dust that can enter the food chain. A coalition of Northwest environmental groups and anti-war activists is considering seeking an injunction to halt the weapons tests.