The Wikipedia article cites for the statement:

>All 320 of the men on duty at the pier died instantly, and 390 civilians and military personnel were injured, many seriously. Among the dead were all five Coast Guard personnel posted aboard the fire barge.[36] African-American casualties totaled 202 dead and 233 injured, which accounted for 15% of all African-American casualties during World War II.[37] Naval personnel worked quickly to contain the fires and to prevent other explosions. Injuries were treated, those seriously injured were hospitalized, and uninjured servicemen were evacuated to nearby stations.[38]

So citation 37 is the way to read more:

> U.S. Army, Redstone Arsenal, Alabama. History. "A Chronology of African American Military Service. From WWI through WWII. Part II". Archived on May 28, 2008. Retrieved January 25, 2010.

The linked page is

https://web.archive.org/web/20080528155224/http://www.redstone.army.mil/history/integrate/chron3b.htm

Here's a fun quote from that article:

>1942 Black newspapers that ran articles strongly criticizing segregation and discrimination in the armed forces had trouble obtaining newsprint until they softened their stance. The U.S. Justice Department also threatened to charge 20 editors with sedition.

On topic:

>1944 By this time, the War Department’s critical need for troops overseas helped to ease opposition to the dispatch of black servicemen to the European or Pacific theaters. The number of African Americans serving in-theater jumped from 97,725 in 1941 to 504,000 in 1943. However, 425,000 black troops remained in the United States. The military claimed that allied foreign nations objected to the presence of black troops, but it was usually American commanders overseas who opposed their assignment.

Italics mine

>Ultimately, though, this incident did result in changes affecting racial relations in the Navy, because ammunition loading ceased to be a "blacks only" assignment. The Navy also adopted safer procedures for loading ammunition.