60 years ago.
Published on Apr 16, 2007 at 2:24 pm.
3 Comments.
Filed under Uncategorized.
April 16, 1947.
This isn’t an astronomical post, but rather a historical one. I grew up in Houston. The events of that date were well before my time, buy plenty of people around remembered them, and growing up in Houston in the 60’s and 70’s, people still talked about what happened. On that date, over 600 people died and over 5000 others were injured in a massive explosion in Texas City, Texas. Nobody really knows how many were killed, and all the bodies were never found. But this ranks as the worse industrial accident in the United States, and one of the worst in the world.
Texas City is located at the mouth of the Houston Ship Channel, just across Galveston Bay from the island of Galveston itself. The prime location makes Texas City a perfect place for chemical plants, refineries, etc. Growing up in Houston, that is the first thing that pops to my mind when I hear of Texas City. And, it was like that in the 1940’s, too.
In 1947, dock workers were loading ammonium nitrate onto the French registered freighter SS Grandcamp. The Grandcamp was a converted Liberty ship left over from World War II. It had already been loaded with small arms ammunition and several other cargo loads. To stabilize the ammonium nitrate and protect it from water, it was packed in a variety of chemicals including paraffin, rosin, and petroleum products. Unfortunately, this also created a mixture similar to that of a high explosive. The mixture was packed in paper sacks and stacked on the dock. No one really knows how the fire started. Some say that the warm temperatures may have made the mixture unstable, and spontaneous combustion happened. Others suggest that a discarded cigarette was the culprit (there were no enforced regulations against not smoking while loading the cargo). But, about 8 am, a fire started in the hold of the ship. When initial attempts to douse the fire with water and fire extinguishers failed to yield much progress, the captain ordered the holds sealed and pumped full of steam. Normally, this deprives the fire of oxygen, and the fire dies. Well, in this case it didn’t work. The heat reacted with the ammunition to release nitrous oxides which helped fuel the fire. Eventually, the hatches of the ship blew off and an eerie colored flame was reported shooting a hundred feet into the air. Soon, the Texas City Volunteer Fire Department was on the scene spraying water onto ship. Texas City is a lazy sort of place, and this was big excitement, so a lot of the town people came out to the docks to watch the fire department put out the fire. A number of children skipped classes, and I have heard that at least one school thought that it might make a good field trip to see how the fire department worked. The, disaster hit.
At about 9:12am, a huge explosion rocked Texas City. It was most likely a two stage explosion. The first was an explosion of gas in the hold of the ship. This explosion was amazingly powerful — so powerful, in fact, that it lifted the ship out of the water and tore it open. With an ample supply of oxygen finally reaching the ammonium nitrate, it also exploded. But, the ammonium nitrate explosion was far more powerful. The Grandcamp exploded with nearly the force of an atomic bomb. In fact, that is what officials in Colorado first thought when they saw the shock waves on seismographs. 
The US military reportedly stepped up its alert status, waiting to see if there were any more explosions. The photo here shows Texas City as seen from Galveston, ten miles away. People in Galveston itself were knocked to their feet, and the wind knocked out of their lungs. At least two aircraft in the vicinity were blown out of the sky. Windows shattered in Houston, 40 miles away. The blast was heard in New Orleans, and some have reported that it may have been heard on the Florida west coast. The downward blast flattened the brand new fire engines of the Texas City fire department, and every one of the city’s firemen were killed. 
The wave from the blast tossed a 30 ton barge moored nearby 100 feet inland. Shards of the ship’s hull were sent shooting outward at supersonic velocities, decapitating people miles away in downtown Texas City. The chemical and petroleum tanks of the chemical plants and refineries in the area were pierced by hot metal fragments, and fires raged everywhere. 
The ship’s anchor was hurled over two miles away. The anchor was later recovered and is part of a memorial to those who died on that day. A nearby ship, the SS High Flyer, also filled with ammonium nitrate, was set on fire. Hours later, it also exploded, adding even more devastation to Texas City. The fires in the refineries burned for over a week until they burned themselves out. Hospitals were overwhelmed. Medical personnel and firefighters from several states away rushed to help, but it was too late for the most seriously wounded. There were 581 known dead, but there were also dozens of seamen, migrant workers, etc, who were not on any official list who were undoubtedly killed.
The firemen who responded to the fire call knew the risk. They knew that ammonium nitrate was an ingredient in high explosives used during the war. Yet, they put their lives on the line as firemen often to to try to prevent what they ultimately could not. And, they paid the ultimate price for that. Let us take a moment to remember their sacrifice 60 years ago today.
-Astroprof
(Photos courtesy Houston Chronicle)
Ed Davies on April 16, 2007 at 4:17 pm: 1
“With an ample supply of oxygen finally reaching the ammonium nitrate, it also exploded.”
Isn’t ammonium nitrate usually the oxidiser?
Astroprof on April 16, 2007 at 5:36 pm: 2
Hmm. I am not sure of the chemistry of explosions, so you might be right. Whatever the reason, though, the second explosion did the most damage, and it came after the first one had lifted the ship out of the water.
Astroprof on April 18, 2007 at 2:48 pm: 3
OK. I asked a chemist who said that ammonium nitrate is a very low grade explosive that is normally used with a booster explosion to provide the shock to make it explode. So, the first explosion lifted the ship up, and that also may be what triggered the second explosion.