Because I work in occupational safety, I pay particular attention to industrial disasters - even though this week has been chock-full of terrible, big news, I find myself drawn to the plant explosion in Texas because of its relevance to workplace safety, something which I have some capacity to understand better than horrific acts of terrorism.

Although the specific causes of the fire and resulting explosion at the West Chemical and Fertilizer Company are as yet unknown, what we do know is that this company stored and distributed large amounts of anhydrous ammonia and ammonium nitrate as agricultural products.

What Is Ammonia?

Ammonia (NH3) is a colorless gas with a particularly pungent odor, and is widely used to serve the nutritional and pharmaceutical needs of terrestrial life - about 80% of ammonia is used (either as salts or solutions) as fertilizer for crops or as an antimicrobial agent in food products. Its basic property allows it to combine with acids to form salts - with hydrochloric acid, it forms ammonium chloride. With nitric acid, it forms ammonium nitrate.

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Ammonia has an exothermic reaction when exposed to water and nitrogen, which means that it releases a significant amount of energy in a short period of time, usually in the form of heat, light and sound. In other words, it's potentially explosive.

Anhydrous ammonia is a commercial term that emphasizes the lack of water in the material. Having a boiling point of -33.34 degrees Celsius (-28.012 degrees Fahrenheit) at a pressure of 1 atmosphere, it must be stored under high pressure or at an extremely low temperature.

Ammonium Nitrate

Ammonium nitrate (NH4NO3) exists as a white crystalline solid. Its property as an oxidizer is why it's used in explosive devices as well as fertilizer. The safety guidelines for storage of ammonium nitrate require that it be segregated from urea and acetic acid, and fire fighting measures require the use of flooding quantities of water rather than jets of water - remember ammonia's exothermic properties? On a scale from 0 to 4, the NFPA rating for reactivity is 3.

Previous Disasters

On April 16, 1947 (the third week of April seems to be historically significantly hazardous) the SS Grandcamp was docked in the Port of Texas City. Along with some small arms ammunition and machinery, it carried about 2,300 tons of ammonium nitrate. The Grandcamp had diverted to the Port of Texas City after being denied berth in Houston, where the port authority had prohibited the loading/un-loading of ammonium nitrate.

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At approximately 8:00 AM that morning, smoke was spotted in the cargo hold of the SS Grandcamp, possibly started as a result of a crewman flicking his lit cigarette away (extinguish your butts, people!). The crew of the ship unsuccessfully fought the fire for about an hour - every attempt to douse it or control it failed, and a red glow reappeared each time.

By 9:00 AM, spectators had started to gather in the harbor, noting that the water around the ship had started to boil. They watched as the captain of the ship ordered his crew to try to extinguish the flames by piping steam into the cargo hold, increasing the internal pressure of the cargo hold so much that the sides of the ship began to bulge.

The vessel detonated at 9:12 AM. The spectators who had gathered to watch the fire, believing they were a safe distance away, were obliterated. The blast was so huge that it caused a 15-foot wave that traveled nearly 100 miles away from the coast of Texas.

Death and Destruction on a Massive Scale

In Galveston, 10 miles away, people were knocked off their feet from the force of the blast. In Louisiana, 100 miles away, people felt the shock of the explosion. Airplanes, flying nearby, were ripped apart. The detonation of the SS Grandcamp is considered to be one of the world's largest non-nuclear explosions, and is the worst industrial disaster in U.S. history.

The official casualty count was 567, including all of the crew of the SS Grandcamp, but this may well be inaccurate as many of the victims were burned to ashes or blown to tiny bits. A single member of the Texas City volunteer fire department survived. Fire departments from nearby areas were unable to approach the site of the explosion because of the intensity of the resulting fires. About 5,000 people were injured, mostly by shrapnel.

The first explosion of the SS Grandcamp ignited the SS High Flyer, which was moored nearby and also carried 961 tons of ammonium nitrate. 15 hours after the initial explosion, the SS High Flyer also detonated, killing at least two more people.

The Texas City Disaster resulted in the first class-action lawsuit filed against the United States government on behalf of 8,485 victims. Industrial re-construction costs incurred as a result of the disaster eventually reached an amount of $100 million (in 1947 dollars - the equivalent cost today would be about $1.03 billion).

Occupational Health and Safety

Although OSHA is a federal agency, many states have their own Occupational Safety and Health agencies, which have adopted the federal regulations and may impose stricter state regulations if they deem it necessary. They may not, however, remove any of the federal regulations.

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Texas is not an agreement state, so federal OSHA has jurisdiction over all of the regulated workplaces there. Many news organizations have noted that the West Chemical and Fertilizer Company had not undergone an OSHA inspection since 1985.

This does not surprise me, for several reasons:

OSHA cannot perform planned or regular inspections for every workplace under its jurisdiction - it doesn't have the time or the manpower to do so. Instead, OSHA's inspection priorities fall in this order:

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-Imminent Danger Situations: Workplace hazards that could immediately cause serious injury or death get top priority. Compliance officers will ask employers to remove potentially affected employees and correct the hazard.

-Fatalities and Catastrophes: Incidents that involve a death or the hospitalization of three or more employees will trigger an inspection. This is the type of inspection that OSHA will conduct regarding the West Chemical and Fertilizer Company. I'll be reading that report when it's released, believe me - but high-profile and high-casualty inspections take a long time to complete. I estimate that this one may take up to a year.

-Complaints: Allegations of hazards or violations, which may be filed by employees anonymously. (I've dealt with this type of inspection myself - it took three months to resolve.)

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-Referrals: Information regarding hazards that come from sources outside the company, such as the media, other regulatory agencies or other companies.

-Follow-ups: Personal verification of abatement for hazards identified in previous inspections.

-Planned or Programmed: These inspections target high-hazard industries, or companies that experienced a high rate if work-related injuries or illnesses.

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So you can see that the West Chemical and Fertilizer Company, not belonging to a specifically high-hazard industry may well escape the attention of OSHA for a long period of time, especially if they've had otherwise good or fair safety records.

Environmental Protection

Another aspect that must be considered in the case of this plant explosion is the company's relationship with the Environmental Protection Agency. Like OSHA, the EPA is a federal agency but may not have direct jurisdiction in every state. My state, for example, is an agreement state with the EPA as well. The guidelines here are similar - states with individual environmental agencies must adopt all of the federal regulations and may impose additional regulations if necessary.

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Outside of the state-run agencies, however, the EPA requires companies to provide notification when those companies exceed certain thresholds of hazardous substances. This information is vital, because the EPA disseminates the information to the state and local emergency response organizations. This is how first responders are made aware of the hazards of any given workplace, should they need to respond to an emergency.

What I'm curious to know is whether or not the West Chemical and Fertilizer Company was in compliance with this notification. We know that ammonium nitrate reacts with water and that the recommended method of extinguishment for a fire that involves ammonium nitrate is flooding - not fire hoses.

It's too early to know whether or not the firefighters of West were aware of the hazards associated with the plant - it's possible that the explosion was unavoidable, the conditions being set after a certain point because of the initial fire. And of course, it's too early to know exactly what caused the fire in the first place.

UPDATE REGARDING WEST CHEMICAL

According to this article in the NY Times, West Chemical and Fertilizer company had reported quantities of 540,000 pounds of ammonium nitrate and 110,000 pounds of anydrous ammonia to the EPA. So, my previous question about whether or not West Chemical had reported over-the-threshold quantities of the ammonium compounds has been answered in the affirmative. However, the article states that the reporting was done late last year, which is concerning. If this reporting is the type I'm thinking of, the numbers should have been submitted by March 1st of last year and of this year - so at face value, it looks like the company wasn't quite on top of it.

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It also seems as though the plant was so old that it was grandfathered into regulations back in 1962, and should have completed a re-authorization process in 2004. It didn't.

Explosive Numbers

The SS Grandcamp was carrying 2,300 tons of ammonium nitrate. West Chemical last reported 270 tons.

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Multiply this explosion by 8.5, and you might have some idea of the size of the Texas City Disaster: