On the night of July 17, 1944, a massive explosion rocked the Port Chicago Naval Magazine, located about 30 miles northeast of San Francisco. Two cargo ships loading high explosives for the Pacific Theater blew apart in a flash that produced a 3-mile-high fireball and seismic shocks felt as far away as Nevada. Instantly, 320 men were killed—202 of whom were African American enlistees—and over 390 others were wounded.
At the time, the United States Navy was strictly segregated. Black sailors were routinely denied combat roles and assigned to dangerous, labor-intensive duty loading live ordnance onto ships without adequate training, safety equipment, or oversight. Officers, who were exclusively white, frequently rushed loading crews into unsafe competitions to increase tonnage rates.
The blast flattened the surrounding base and completely destroyed nearby towns. Less than a month later, surviving Black sailors were ordered to resume loading munitions at the nearby Vallejo naval station under identical hazardous conditions. Traumatized and aware that no safety reforms had been enacted, 258 sailors refused the order.
After threats of execution, 208 returned to duty, but 50 men stood firm. The Navy charged these 'Port Chicago 50' with mutiny during wartime. Represented in part by Thurgood Marshall, the men were nonetheless convicted and sentenced to 15 years of hard labor.
However, public outrage and legal appeals eventually forced the Navy to review the trial, leading to early releases in 1946 and accelerating the complete desegregation of the U. S. Armed Forces in 1948.