Anhydrous ammonia is a chemical commonly used as nitrogen fertilizer, that when handled improperly, can be dangerous.
Anhydrous ammonia is a chemical commonly used as nitrogen fertilizer that, when handled improperly, can be dangerous. HB 1898 and SB 750 give regulatory authority to the Missouri Air Conservation Commission rather than the Missouri Department of Agriculture and also establish registration and tonnage fees for facilities that store anhydrous ammonia.
Anhydrous ammonia is a colorless gas that is one part nitrogen and three parts hydrogen (NH3), often stored under pressure as a liquid. “Anhydrous” refers to the chemical purification to remove water, in contrast to aqueous ammonia which is dissolved in water. Anhydrous ammonia is a commonly used fertilizer.1,2 Fertilizers provide essential elements for crop production, and nitrogen fertilizers are roughly estimated to support crop production for half the world’s population.3,4 Anhydrous ammonia is also used as a refrigerant, as well as in textile and chemical manufacturing.5 Anhydrous ammonia may also be used illegally make methamphetamine, which presents a potential theft and safety hazard to storage facilities.6
If handled improperly, anhydrous ammonia is a toxic inhalation hazard.7 Anhydrous ammonia reacts rapidly with water to form ammonium hydroxide. The dehydration and alkalinity from this reaction can irritate the skin, eyes, and throat. Anhydrous ammonia has a distinctive smell detectable at concentrations as low as 5 parts per million (ppm), which can serve as a warning of release. Short exposures at 220 ppm can result in severe injury including chemical burns and lung damage, and short exposure to 2700 ppm can result in death.8
All nitrogen fertilizers, including anhydrous ammonia, can ultimately convert to nitrate in the soil, particularly with warmer temperatures.9 Excess nitrate runoff can lead to eutrophication (also known as algae blooms), and is a primary driver for hypoxia (low oxygen) and dead zones, such as those in the Gulf of Mexico.9 Elevated nitrate levels (10 mg/L) in well water is a health concern for developing fetuses and infants, as nitrate interferes with acquisition of oxygen from the bloodstream, resulting in “blue baby syndrome”.10 High nitrate levels in drinking water can also increase cancer risks.11,12 Nitrogen applications can increase air pollution, as ammonia can volatilize.13 However, this is not common in Missouri, as the generally acidic soils tend to adsorb nitrogen.9 Good management practices for nitrogen fertilizer application can promote efficient use for maximizing crop yield while preventing nitrogen runoff.14,15
Federally, anhydrous ammonia is regulated by several agencies.16 The Clean Air Action Section 112 grants the Environmental Protection Agency (EPA) to regulate facilities with greater than 10,000 lbs of anhydrous ammonia onsite. The Clean Air Act requires facilities to complete an accident history report, create a Risk Management Plan, analyze a worst-case scenario, and coordinate with local emergency response. The Emergency Planning and Community Right-to-Know Act also requires emergency planning and response procedures for facilities with over 500 lbs of anhydrous ammonia, and reporting chemical releases. The Department of Homeland Security requires risk assessment plans for certain facilities located on waterways or with greater than 10,000 lbs of anhydrous ammonia. The Occupational Safety and Health Administration (OSHA) regulates storage and handling.
Currently in Missouri, under Chapter 266.355 RSMo, anhydrous ammonia is regulated by the Missouri Department of Agriculture Division of Weights, Measures and Consumer Protection. Specifically, the division performs safety inspections of bulk storage facilities, nurse tanks (transportation vessels), and applicators.17
HB1898 and SB790 repeal the Department of Agriculture’s oversight authority over standards relating to anhydrous ammonia, and authorizes the Air Conservation Commission to adopt, promulgate, amend, and repeal rules and regulations related to the use, storage, or selling of anhydrous ammonia. The bills also create the "Anhydrous Ammonia Risk Management Plan Subaccount" within the Natural Resources Protection Fund, which shall consist of fees required in these provisions, such as annual registration of $200 for retailers who use, store, or sell anhydrous ammonia that is an air contaminant source.