On April 16, 1947, a large steel ship filled with a similar amount of ammonium nitrate exploded in Galveston TX. The huge explosion literally blew the ship to bits. It threw gigantic pieces of steel so high, they didn’t rain down for a long minute. The ship’s 1.5 ton anchor landed a mile and half away. More than 500 people were killed and the explosion blew down many buildings.
The 1947 explosion you described actually occurred in Texas City on Galveston Bay, not in Galveston (about 10-15 miles SE).