DOTHAN FIRE DEPARTMENT Chief Dennis L. Rubin Personnel: 174 career firefighters Apparatus: 12 paramedic engines, two ladder trucks, one heavy rescue, two battalion chiefs, one rehab unit, one air-and-light truck, one rescue trailer, one customer service unit Population: 60,000 Area: 83...
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Because of the quantities of hazardous materials kept on site, the plant is required to file a "Tier II" report annually. These reports are copied and carried aboard the fire department's hazmat units and both battalion commanders' vehicles. This information makes for a great initial reference source at incidents such as this one.
Most of the structures at Tri-State are multi-story, non-combustible buildings. They are constructed of a steel framework assembly covered by corrugated steel panels. A building of this type does not add to the fire loading; however, it will collapse rapidly during fire exposure as the heated metal (lightweight steel) fails at about 1,000 degrees Fahrenheit. Further, all of the buildings in the manufacturing areas were covered with several inches of a dusty product residue. Our concern was for the potential for a dust explosion if there was an ignition of the anhydrous ammonia during this incident. That ignition did not occur, but we had planned for this possibility by stretching several 13/4-inch attack lines to the exposure buildings.
Many large fixed-storage tanks are located at this plant. The tanks store the various raw materials needed for the fertilizer manufacturing process. The hazmat leak that we experienced was from the bulk anhydrous ammonia storage tank area. The plant has two 18,000-gallon tanks and one 14,000-gallon tank that supply a manifold piping system that flows through a high-pressure pump leading into the production area. The pipe had sheared off at a relief valve flange near the tank closest to the building. The break was about one inch in diameter, operating at about 700 psi, and the pipe had been leaking for nearly six hours.
It was estimated that 6,000 gallons of product leaked out into the community. The cause of the pipe shearing off is of great concern to the nearby neighborhoods. The Federal Bureau of Investigation (FBI) arrived on location a few hours into the incident and took over the cause investigation. At press time, no information has been released by the FBI about the cause of the leak.
About The Leaking Product
Anhydrous ammonia is a colorless gas with a very pungent odor. Although the government allows it to be classified as a nonflammable gas, it will burn in the range of 16-25%. Of course, the fire hazard of anhydrous ammonia greatly increases when in the presence of oil, LPG, gasoline and other flammable materials.
Many of these products were close to the leaking pipe. The vapor density of the material is 0.6, meaning it is lighter than air. In our case, however, due to the 100% humidity and light winds, the releasing ammonia vapor turned into a huge, lingering vaporous cloud. This cloud engulfed the plant area as well as the surrounding neighborhoods.
Anhydrous ammonia has a great affinity for water. The National Institute of Occupational Safety & Health (NIOSH) describes this affinity as a water solubility of 34%, meaning that the material readily mixes with water. This feature of the product proved helpful later in the incident.
Health concerns include direct contact to the body or inhalation exposures. When anhydrous ammonia comes in contact with human cells, it is corrosive. Expect irritation, burns, shortness of breath, chest pains and pulmonary edema if long-term or high-concentration exposure occurs. Further, there is a risk of a thermal burn (frostbite) as the liquefied product returns to a gaseous state.
Treatment protocols for exposure to this chemical are simple and straightforward: Any victim must be relocated to fresh air; exposed areas are flushed with lukewarm water for at least 15 minutes; contaminated clothing is removed; and the patient receives appropriate advanced life support care and is transported to a medical facility. With more than 30 people needing some level of emergency medical care, this information was referenced early and often.
Eight strategic goals were addressed in our incident action plan at this alarm:
- 1. Incident command system.
- 2. Deny access and control the outer perimeter.
- 3. Evacuate the impacted citizens and visitors.
- 4. Provide shelter for the evacuees.
- 5. Stop the leaking product.
- 6. Handle other emergency alarms.
- 7. Activate the EOF and EOC for regional support.
- 8. Incident demobilization and recovery.