Wouldn’t there have been a large janitorial, menial and kitchen staff? I can imagine those jobs having a good percentage of black workers, even in (if not especially in, considering the location) the forties.
The Pentagon’s probably seen several generations of modernisation since the 1940s. Whatever the original figures were they will have changed by now. Lot more women’s facilities, I’d guess.
Truman was the one who signed Executive Order 9981 requiring the armed forces to de-segregate, in 1948
“I’m sorry, it is against the interests of national security to discuss our soldiers’ movements, lest we give the enemy something to go on.”
A few years ago, I learned that OSHA’s rule says you must have one toilet for every 150 workers. The Pentagon, of course, was built before OSHA.