I am fairly certain that this forlorn abandoned factory building along the north side of Stratford Avenue is the remnant of the massive army munitions plant that manufactured arms during World War II.
It featured a gigantic vaulted steel building that looked like it had horns sticking out of its roof.
Built St. Louis has a whole page on it.
From what I understand, the whole site is polluted now.
Long term I don’t know what is planned for this site, sitting abandoned as long as it has been.