Anhydrous Ammonia

What is the problem?

Anhydrous ammonia, a colorless gas with pungent, suffocating fumes, is used as an agricultural fertilizer and industrial refrigerant.

When handled improperly, anhydrous ammonia can be immediately dangerous to life or health. As liquid anhydrous ammonia is released from its container into the air, it expands rapidly, forming a large cloud that acts like a heavier-than-air gas for a period of time. Because the vapors hug the ground initially, the chances for humans to be exposed are greater than with other gases. Symptoms of anhydrous ammonia exposure include:

• eye, nose, and throat irritation
• breathing difficulty, wheezing, or chest pain
• pulmonary edema, pink frothy sputum
• burns, blisters and frostbite.

Exposure can be fatal at high concentrations.

Anhydrous ammonia is also a key ingredient in the production of methamphetamine (meth), an illicit activity frequently occurring in makeshift laboratories. Because states require a license for purchase of anhydrous ammonia, those involved in illicit production of meth often resort to stealing it from areas where it is stored and used (e.g., farms, industrial refrigeration systems, and railroad tanker cars). These thefts often lead to releases when valves are left open as ammonia is being siphoned, ammonia is transferred inappropriately into makeshift containers, plugs are removed from ammonia lines at refrigeration facilities or the wrong hoses or fittings are attached to storage containers. This creates a health hazard for anyone in the proximity including emergency health responders.

Who’s at risk?

The use of chemical fertilizer containing anhydrous ammonia can lead to exposure. Outdoor exposure to high levels of anhydrous ammonia can result from leaks and spills at production plants and storage facilities, and from pipelines, tank trucks, railcars, or ships and barges that transport ammonia.

Another possible exposure to anhydrous ammonia results from the theft of ammonia by “cookers” of methamphetamines. Of the 40,349 events reported to the Hazardous Substances Emergency Events Surveillance (HSEES) system from January 1, 2000 to June 30, 2004, a total of 1,791 (4%) were associated with illicit meth production. Of these 1,791 events at least 164 were known to have been caused by anhydrous ammonia theft for the production of methamphetamines. These 164 events resulted in 85 injured persons, mostly members of the general public and police officers. The most frequent injuries were respiratory distress and eye irritation. However, these numbers are not completely representative of the number of incidents or injuries, since only 16 states contributed data to HSEES during that time period and reporting is not mandatory for all events. In addition, law enforcement officials might not report events that could jeopardize criminal investigations.

How can risk be reduced?

The best ways to reduce risk of serious injury from anhydrous ammonia exposure are to wear protective equipment and to know what to do in an emergency. Before entering an anhydrous ammonia release zone, emergency responders should select the proper personal protective equipment (PPE) including positive-pressure, self-contained breathing apparatus and chemical-protective clothing. The best first aid treatment for anhydrous ammonia exposure is to flush skin and eyes with water for at least 15 minutes.

Those who work with anhydrous ammonia or who respond to an ammonia release can take the following precautions:

• Always keep 5 gallons of clean water in your supply tank and carry a small squeeze bottle.
• Understand first aid treatment and practice what you would do in an emergency.
• Wear ventless goggles, rubber gloves, and a long-sleeved shirt when working with anhydrous ammonia.
• Regularly inspect equipment and have worn hoses and valves replaced.
• Never allow bystanders in the area where anhydrous ammonia is being transferred or applied.
• Review instructions before coupling and uncoupling lines.

The Bottom Line

• Increased exposure risk can result from anhydrous ammonia leaks at storage facilities or from means of transportation. These leaks may require evacuation and the use of emergency personnel and procedures. Respiratory distress and skin and eye irritation may result from anhydrous ammonia exposure and high levels of exposure may result in death. Advance safety preparation and precautions and/or rapid emergency response can lessen the possibility of serious injury.
• Although most anhydrous ammonia is used for legitimate purposes, a small percentage is diverted to meth manufacturing. Since meth production is illegal, meth “cookers” may attempt to obtain a supply of ammonia by stealing it from storage facilities. This theft can result in the release of ammonia into the air due to removal of plugs or opening of valves during the transfer process or the use of inadequate containers, hoses or fittings. This presents a dangerous risk of exposure not only to those involved in the theft, but also to the emergency responders or innocent bystanders.

Case Example

John and Sarah are returning home from an evening celebrating John’s parents’ 50th wedding anniversary. As they are driving along an isolated stretch of I-10, John notices an approaching car in his rearview mirror. The car pulls out to pass and John, hearing the faint sound of a siren, catches the sight of a flashing blue light some distance behind him. Just as the car passes, it careens into the path of John and Sarah’s car, clipping the front end and forcing both cars off the road and down the embankment. After checking on Sarah, John, clearly shaken, extracts himself from the deployed airbags and staggering toward the other vehicle is almost immediately overcome by fumes and collapses. Shortly thereafter, a police officer arrives on the scene. He has been chasing the car following the theft of anhydrous ammonia from a storage facility. Knowing that such thieves often use inadequate storage containers for the ammonia, he has contacted emergency personnel who arrive on the scene quickly. Wearing protective equipment, they are able to rescue John and Sarah and to extract the thief from his car, moving them all a safe distance from the fumes. It is clear that the driver was overcome by fumes leaking from the storage tank he had used for the theft and lost consciousness while attempting to pass John and Sarah.