This decision concerned an application for summary judgment in a lawsuit brought by an environmental coalition, which sought to stop the US Navy from using, in most of the world's waters, Low Frequency Active ("LFA") sonar. It followed an earlier preliminary injunction ordered by the Court in favour of the plaintiffs. In the light of various findings of non-compliance with US legislation, the Court issued a permanent injunction to permit the Navy to train and test LFAS in a wide range of oceanic conditions as needed, while restricting it from operating in certain sensitive areas when marine mammals are particularly abundant.