There was a similar accident in Galveston Harbor in the 30’s, IIRC, with Ammonium Nitrate. Apparently, they didn’t realize you couldn’t just fill the hold of a freighter with loose fertilizer and there was a delay in leaving the port that allowed the internal temperature to rise to spontaneous ignition.
SS GRANDCAMP - Texas City , across bay from Galveston
2500 tons Ammonium nitrate fertilizer in hold destined for
France
Fire started in cargo hold, captain not wanting to ruin cargo by pouring water in hold sealed hatches and flooded
hold with live steam from engine room to smother fire
Bad Move - ammonium bitrate is oxidizer, has own oxygen
also nitrate has been treated with wax and rosin for water
resistance - equally bad move as sensitized it and converted
it to high explosive
By sealing hatches and injecting steam raised temperature and pressure to detonation point
SS GRANCAMP exploded just after 9 am - wiping out entire Fire department on dock
Set fire to Monsanto petro chemical works nearby
Another freighter loaded with fertilizer SS HIGHFYER was set on fire and disabled by initial blast - attempts to tow it clear failed and exploded at 1am following morning adding
to carnage.
Death toll estimated at 547, considered low