Plans for a massive sea and air warfare training range along 50,000 square miles off the Southeast coast have been released by the U.S. Navy, according to the U.S. Fleet Forces Command.

The final Environmental Impact Statement is available at

Environmental groups are scrutinizing the range, where the Navy would hold training and testing exercises, sometimes using active sonar and explosives. The groups say the noises could deafen and be lethal to marine mammals such as whales and dolphin that navigate by echolocation.

As the range is planned, construction is underway of a 500-square-mile grid of transmitters and receivers connected by cable, lying on the ocean floor off Jacksonville, Fla. Navy submarines and ships would conduct training exercises across that grid. Environmental groups have sued in federal courts to stop it, lost the first round and are waiting a ruling in the second round, said Catherine Wannamaker, of the Southern Environmental Law Center.