09/03/2009 05:12 am ET Updated May 25, 2011

Fertilizer Chemical Linked to Toxic Blaze

A toxic brew erupted last week, and not just of the political kind. As the nation preoccupied itself with beer consumption at the White House, an incendiary event of a different sort took place some 1,200 miles away in Bryan, Texas.

In this small city north of Houston, tens of thousands of residents were forced to flee their homes when a chemical fire erupted at the El Dorado Chemical Plant. The emergency evacuation covered a 275-square mile radius that included the Texas A&M University campus.

Local media coverage described an unnerving scenario, one with fiercely burning flames and a black cloud that enveloped the area. One account reported a "plume of smoke extending more than 60 miles." Several dozen residents were treated at emergency rooms for smoke inhalation and other ailments linked to the accident.

Just what accounted for the ferocious nature of the inferno? The warehouse going up in flames housed ammonium nitrate. That's the chemical that is so incendiary it's been used to blast quarry and fuel rockets. It's also linked to for more nefarious acts including the 1995 bombing of a federal building in Oklahoma City. (Among the items Timothy McVeigh and Terry Nichols relied on to build their deadly bomb were more than 100 bags of ammonium nitrate).

In recent years, the substance has hampered U.S. troops in Afghanistan. Having run out of the munitions left over from the war with Russia in the 1980s, the Taliban have discovered that the chemical, when mixed with diesel or gasoline, makes an effective -- if rudimentary -- roadside bomb.

Ammonium nitrate has another use, one that keeps plants like the one in Bryan in business. It's a common -- and inexpensive -- ingredient found in fertilizer. That's right: The chemical arsenal Americans rely on to help cultivate crops turns out to be the same one used for warfare and acts of domestic terrorism.

The Arkansas-based El Dorado Chemical Co. manufactured fertilizer at its plant in Bryan, billing itself as a company that "plays a vital role in agriculture," according to the company's Web site. It promotes itself as a place where customers can "pick up truckloads of ammonium nitrate...24 hours per day, 7 days per week."

That's a tricky proposition. What the company's Web site doesn't mention is how the material -- while effective in bolstering crops -- can be a major fire risk and has already resulted in many documented cases of detonation and explosion. Stockpiling ammonium nitrate is notoriously difficult and dangerous.

In the past decade alone, there have been several accounts of explosions resulting from the storage and transportation of fertilizer including a 2001 explosion at a fertilizer factory in Toulouse, France and a 2003 explosion at a fertilizer storage facility in Murcia, Spain.

Five years ago, one of the deadliest explosions involving ammonium nitrate occurred in North Korea. Unlike the event this week in Texas, the incident in North Korea had far more deadly consequences, resulting in 162 deaths and the destruction of nearly 8,000 homes.

Recent efforts to regulate fertilizer in this country have focused on the link between fertilizer run-off and water quality with some municipalities acting to curb application and eliminate the use of phosphates (another common ingredient in fertilizer). But efforts to regulate ammonium nitrate for security reasons have been less successful, despite support from some legislators.

Officials in Texas said they were investigating whether a rogue spark that escaped from a welder's tool was responsible for igniting the fire in Bryan and the state's Commission on Environmental Quality said no harmful omissions have been detected in the air surrounding central Texas.

El Dorado has pledged to conduct an internal review and issued a response to the fire via its Web site: "We deeply regret the enormous inconvenience this incident has caused residents and business in Bryan and College Station as well as other nearby Communities," the statement read.

Even so, the incident serves as a sobering reminder of the incendiary nature of ammonium nitrate that manufacturers continue to churn out in massive quantities in response to an agricultural industry that demands it.