11 Iowa City Workers Treated for Anhydrous Ammonia Inhalation

Iowa City, Iowa – Sixteen (16) meatpacking workers were taken to an area hospital after suffering inhalation injury from an anhydrous ammonia leak at a West Liberty plant. The tank is on the roof and according to the report it came into the plant area. Workers were treated for minor to moderate inhalation injury. The leak was caused when a suction header failed allowing 30 gallons or liquid ammonia to fall onto the roof. The value was shut off after approximately 10 minutes. Both reports identified the plant as the West Liberty Foods plant that processes turkeys.

Here is one from the Princeton, Illinois Fire Department. It seems to be the best having more information about the chemical. Containing the vapors is achieved with spraying water over the gases that are leaking and vaporizing.

Another method is to use an anhydrous ammonia tarp and cover. Here you will see the Winston-Salem, North Carolina Fire Department Hazmat team demonstrating the “Tarp and Cover” control method.

West Liberty is a small town located in __ Iowa. I’m not so sure I’d every buy a house near this intersection in West Liberty.

Anhydrous ammonia leaks aren’t anything new. The hazards are well known.

Anhydrous ammonia has many industrial uses as well as being used in farming as a way to enrich the soil.

You’ve even have it in your household.

What is a suction header?

I personally don’t know the answer, but here is one explanation from the Free Patents Online site.

Dry suction industrial ammonia refrigeration system - United States Patent 6018958 - A dry suction refrigeration system includes an evaporator fed with liquid refrigerant which discharges a vapor refrigerant to an accumulator. A compressor receives vapor refrigerant from the accumulator and compressies (sic) the vapor refrigerant. A condenser receives the compressed vapor refrigerant from the compressor and transforms the refrigerant into liquid refrigerant. A receiver receives the liquid refrigerant from the condenser and supplies it to the evaporator. The evaporator includes an electronic expansion valve operable to continuously monitor the evaporation of liquid refrigerant in the evaporator and to continuously meter the flow of liquid refrigerant, so as to cause a complete vaporization of the liquid refrigerant. Because the liquid refrigerant is completely evaporated, the vapor refrigerant is moved through the system by pressure differential alone.

What are the uses of anhydrous ammonia? [NH3]

Corp Brothers Inc. provides this valuable explanation.

A colorless , flammable, toxic, alkaline gas shipped as a liquefied gas at its vapor pressure of 116.7 psig at 70°F (21°C). It causes burns on contact with eyes, skin, and mucous membranes.

Anhydrous ammonia is one of the oldest commercial refrigerants known. Its most extensive use (about 80%) is in soil fertilization as a source of nitrogen, which is essential for plant growth. Other uses include metal treating operations such as nitriding, sintering, and furnace brazing. Ammonia is also used the chemical industry to make a host of products. Gunpowder and sulfuric acid are a couple of well known products that use ammonia as an ingredient.

Ammonia is produced primarily by the Haber process whereby nitrogen and hydrogen are combined directly. A less important method is the calcium cyanamide process which produces ammonia directly from limestone, carbon, nitrogen, and steam. Also some ammonia is produced from the destructive distillation of coal.

Under appropriate regulations, anhydrous ammonia is transported as a liquefied compressed gas in cylinders, insulated and un-insulated tank cars, barges, and tankers. It is stored in bulk in large capacity containers installed above or below ground. Normal above ground storage is un-insulated pressure storage tanks. Very large aboveground storage containers are often low pressure, refrigerated, and consequently insulated.

Remember to always protect yourself by knowing the risks and reading the manuals. Better safe than sorry. And as always ... let's be careful out there.