The Port Chicago disaster was a deadly munitions explosion of the ship SS E. A. Bryan on July 17, 1944, at the Port Chicago Naval Magazine in Port Chicago, California, United States. Munitions being loaded onto a cargo vessel bound for the Pacific Theater of Operations detonated killing 320 sailors and civilians and injuring 390 others.

An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated by a slower expansion that would normally not be forceful, but is not allowed to expand, so that when whatever is containing the expansion is broken by the pressure that builds as the matter inside tries to expand, the matter expands forcefully. An example of this is a volcanic eruption created by the expansion of magma in a magma chamber as it rises to the surface. Supersonic explosions created by high explosives are known as detonations and travel through shock waves. Subsonic explosions are created by low explosives through a slower combustion process known as deflagration.