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Friday, May 31, 2013

Regulation of Fertilizers: Ammonium Nitrate and Anhydrous Ammonia



Dana A. Shea
Specialist in Science and Technology Policy

Linda-Jo Schierow
Specialist in Environmental Policy

Scott Szymendera
Analyst in Disability Policy


The explosion on April 17, 2013, at the West Fertilizer Company fertilizer distribution facility in West, TX, has led to questions about the oversight and regulation of agricultural fertilizer. Facilities holding chemicals must comply with regulations attempting to ensure occupational safety, environmental protection, and homeland security. In addition to federal regulation requiring reporting and planning for ammonium nitrate and anhydrous ammonia, most state and some local governments have laws and regulations regarding the handling of either or both of these chemicals.

The West Fertilizer Company possessed a variety of agricultural chemicals at its retail facility, but policy interest has focused on two chemicals: ammonium nitrate and anhydrous ammonia. Ammonium nitrate is a solid that is primarily used as a fertilizer whose use generally occurs without incident. In combination with a fuel source and certain conditions, such as added heat or shock, confinement, or contamination, ammonium nitrate can pose an explosion hazard. Such accidents have rarely occurred, but have historically had high impacts. For example, the ammonium nitrate explosion in 1947 in Texas City, TX, where two ships carrying ammonium nitrate caught fire and exploded, destroyed the entire dock area, including numerous oil tanks, dwellings, and business buildings. The bomb used in 1995 to attack the Murrah Federal Building contained ammonium nitrate as a component of its explosives.

Anhydrous ammonia has a variety of uses, including as an agricultural fertilizer. Many agricultural retailers store and use anhydrous ammonia. In contrast with ammonium nitrate, anhydrous ammonia is a gas more generally viewed as a threat from its inhalation toxicity. It is regulated to prevent release of the chemical into the atmosphere where it might travel as a cloud and impact workers and the surrounding environment.

Various federal, state, and local agencies collect mission-relevant information about chemical holdings. The West facility had reportedly not complied with all relevant and applicable regulatory requirements. For example, the facility reportedly had not contacted the Department of Homeland Security (DHS), which should have received information about any ammonium nitrate or anhydrous ammonia stored at the facility. The extent to which agencies shared relevant information about chemical holdings in order to enable effective regulatory oversight is still unresolved.

As congressional policymakers consider the ramifications of the explosion in West, TX, they may face several policy issues. These policy issues include the:


  • challenges arising from relying on reporting of chemical inventories by regulated facilities; 
  • potential for omission and duplication in existing regulatory reporting; 
  • long intervals between inspection at many such facilities; 
  • ability of federal, state, and local government agencies to share information effectively among themselves; and 
  • public and first-responder access to regulatory information.


Date of Report: May 14, 2013
Number of Pages: 20
Order Number: R43070
Price: $29.95

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