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Ammonium nitrate: At the center of disaster in Texas City and Kansas City

Two incidents, decades apart, highlight the risks of operating near this dangerous compound


Investigators search through a highway construction site, Nov. 29, 1988 in Kansas City, Missouri where two early morning explosions shattered windows over a 10-mile area and killed six firefighters. The firefighters had been fighting a possible fire in a truck, officials said.

AP Photo/Sam Harrel

To gain anything useful from disaster studies, it’s necessary to find the facts. There can be no truth, full or otherwise, without them.

We critique and review incidents of consequence to piece together a narrative of what happened: What worked? What didn’t work? What failed? What almost worked or almost failed? Who did what – and when did they do it?

The more things that pass investigation and contribute to the truth, the better the understanding of the facts of the matter at hand and become part of the narrative. However, depending on the circumstances, getting to the facts may be easy or so difficult that no conclusion may be reached.

Blasts pose unique investigative challenges

In the case of explosions, the inherent destruction means facts are often elusive, and people with critical knowledge of what happened may have been killed or injured.

Witness statements are useful when they can be verified and corroborated, adding previously unknown information to the puzzle. However, some individuals may not want to tell what they know because it could implicate them in some way. Moreover, participants or witnesses may fail to corroborate parts of the story or purposefully obscure or distort what happened.

If there’s no direct evidence or verifiable testimony, a challenge sometimes faced in explosions, we’re left to make a best guess about what happened. This was the case for two significant explosions impacting the fire service.

Two disasters, one explosive compound, many unknowns

There is more that we don’t know than we do know about the 1947 explosion that nearly destroyed Texas City, Texas. The same is true of the 1988 explosion at a highway construction site in Kansas City, Missouri. Ammonium nitrate was the primary factor in both disasters, responsible for the deaths of many firefighters actively engaged in fire suppression.

Ammonium nitrate is a chemical compound widely used in various industries: agriculture, mining and quarrying, construction, pyrotechnics and weaponry. It is a strong oxidant that reacts with acids, combustibles and reducing agents, and emits irritating toxic fumes when burning.

By itself, this compound is not combustible; however, it enhances the combustion of other substances. Additionally, it decomposes when exposed to heat, causing it to emit expanding gases. When ammonium nitrate is confined in a container or a storage facility, those gases can become trapped, increasing pressure over time and greatly elevating the force and destructive power of an explosion. The risks increase as temperatures rise.

Ammonium nitrate can become more sensitive to decomposition if contaminated with organic materials, fuels, metals or other catalysts. This effect can lower the temperature threshold at which ammonium nitrate begins decomposing. Such contaminants are often combustible, further increasing the risks.

Texas City, 1947: The deadliest industrial accident in U.S. history

On April 16, 1947, around 8 a.m., a fire of undetermined origins started in the cargo hold of the SS Grandcamp. The ship’s cargo consisted of pelletized ammonium nitrate.

As unsuspecting firefighters battled the flames, heat and pressure built until the ammonium nitrate reached an explosive threshold. The ensuing blast was massive, setting off multiple fires in the area, with the shockwave forming a 15-foot tidal wave.

The blast killed approximately 600 individuals, including all 30 firefighters who had been working on the docks near the burning ship – 27 of the 28 members of the Texas City Volunteer Fire Department and three of the four members of the Texas City Heights Volunteer Fire Department. Of the hundreds killed, many were school-aged children who had ridden their bikes to the dock area to watch the burning ship. It is likely that many others died in the area but their whereabouts were never accounted for in the aftermath.

An additional 4,000 were injured in the blast.

More than 24 hours later, on April 17, a second ship, High Flyer, also exploded. This ship held an additional 961 tons of ammonium nitrate. Due to the area having been evacuated, many fewer people died as a direct result of this blast; however, the heat and intensity of the explosion was so great that pieces of High Flyer’s frame glowed with heat and rained down all across Texas City, starting numerous fires.

It’s no understatement to say this disaster nearly wiped Texas City off the map. The many fires caused by the blasts burned for a week, as approximately 200 firefighters, some from as far away as Los Angeles, traveled to Texas City to battle the flames. All four of the fire department’s engines had been destroyed in the blast.

Kansas City, 1988: Ammonium nitrate’s deadly margin of error

In the early hours of Nov. 29, 1988, six city firefighters were killed in an explosion involving a storage unit containing 25,000 pounds of ammonium nitrate that had been used for blasting through limestone cliffs at a highway construction site.

The explosion was set off by an apparent arson fire near an unmarked (no hazmat placard) storage trailer. The police long thought this disaster was related to a labor union dispute. Prosecutors, however, would later claim that the fire was set to divert security guards so that people from the neighborhood could steal tools from the construction site.

At least one police detective saw an obvious flaw in this theory: Both security guards had left the site at the same time and were not around to be distracted. The security guard whose truck was destroyed in the incident later admitted under oath to involvement in a separate automotive insurance fraud scheme.

Regardless of how the fire started, the firefighters likely did not know what was in the trailers. And if they did know, based on either knowledge of local blasting operations or even a placard, they may still not have appreciated the great hazard they faced.

Four of the six firefighters, including the two company officers, had completed the NFA HazMat Recognizing and Identifying Hazardous Materials training courses. Additionally, the official information contained in the DOT Guidebook carried in the firefighters’ apparatus, coupled with their local knowledge of the site, may have been insufficient to warn them of the magnitude of the hazard. At that time, there was no requirement for placards on on-site explosives storage lockers.

The cost of change

When firefighters are killed in the line of duty, we seek information to explain and learn from the tragedy. And when such deaths occur from the acts or failure to act of others, we seek justice for the fallen.

In the Texas City disaster, there remains to this day a lack of information to fully explain what happened. At a minimum, we can say that the local government of Texas City should have had a general plan for emergencies, but it did not; only the larger companies doing business in the city had such plans.

In Kansas City, a place with a long history of deadly explosions, the deaths of the six firefighters hit hard. There was a need to seek justice for the fallen and their families, but it did not go well. In fact, the incident continues to raise questions to this day, with far too many still unanswered.

These two explosions did, at least, impact the rules and procedures for handling hazardous materials and for responding to the accidents that occur, especially with ammonium nitrate. Still, although the potential for accidents of this nature has lessened in the U.S. and elsewhere thanks to what’s been learned, ammonium nitrate remains every bit as dangerous today as it was in 1947 and 1988. The August 2020 blast in Beirut, which produced one of the most massive explosions in recent history, serves as a devastating reminder of those dangers.


Bruce Hensler served as a firefighter from 1976 to 2011 in career, combination and volunteer departments. He previously served as a fire program specialist in the Emergency Response Support Branch of the U.S. Fire Administration, retiring in 2017. He also previously served as deputy director of the operations division for the firefighter training program in Maine. Hensler has a master’s degree in public administration. His interest in history led him to write “Crucible of Fire: Nineteenth-Century Urban Fires and the Making of the Modern Fire Service.” More information about his book is available at Connect with Hensler on LinkedIn.