A gun turret explodes on the USS Iowa, killing 47 sailors.

A gun turret is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in some degree of azimuth and elevation.

On 19 April 1989, an explosion occurred within the Number Two 16-inch gun turret of the United States Navy battleship USS Iowa (BB-61) during a fleet exercise in the Caribbean Sea near Puerto Rico. The explosion in the center gun room killed 47 of the turret's crewmen and severely damaged the gun turret itself. Two major investigations were undertaken into the cause of the explosion, one by the U.S. Navy and then one by the Government Accountability Office (GAO) and Sandia National Laboratories. The investigations produced conflicting conclusions.

USS Iowa (BB-61) is a retired battleship, the lead ship of her class, and the fourth in the United States Navy to be named after the state of Iowa. Owing to the cancellation of the Montana-class battleships, Iowa is the last lead ship of any class of United States battleships and was the only ship of her class to serve in the Atlantic Ocean during World War II.