Editor’s Note: This article is dedicated to the firefighters who were killed when an ammonium nitrate explosion occurred at the West Fertilizer Company storage and distribution facility in West, TX.
There is a wide range of chemicals that have the potential to create a reactive hazard. A chemical reactive hazard can occur when incompatible chemicals are mixed, creating a situation that can pose a threat to people, property and the environment. This is why reactive chemicals, be they in transit or at a fixed facility, should always be properly identified and stored.
Both the chemical industry and various regulatory bodies, including the Environmental Protection Agency (EPA), the Occupational Safety and Health Administration (OSHA) and the Consumer Product Safety Commission (CPSC), are responsible for managing chemical reactive hazards. However, even with both self-imposed and mandated safeguards, accidents still occur.
One substance with the propensity to create a chemical reactive hazard is ammonium nitrate (AN). In fertilizer form, AN has been involved in several recent incidents in the state of Texas. As a result, agencies have revitalized the discussion for more regulatory coverage of this and other types of reactive chemicals.
An explosive compound
AN is a crystalline solid that’s widely used as an artificial fertilizer; it’s also used in explosives, blasting agents and propellants due to its strong oxidizing potential. AN (NH4NO3) is formed when the hydrogen in nitric acid (HNO3) is replaced with ammonia. Because of its oxidizing properties, AN supports and accelerates combustion involving organic materials, therefore increasing the potential for a fire or explosion.
The storage and handling of AN-based fertilizers has garnished the most attention from officials over the years, in large part because granulated AN will melt at approximately 337 degrees F. When this occurs, there is a release of toxic gases that contain nitrogen oxides, which support combustion in the absence of oxygen. Heat and pressure will build if the product is in a confined space and the weight of the product has caused compaction.(1) As the chemical reaction continues and the heat/pressure build, an explosion is likely to occur.
Although there have been few instances of fire or explosions involving large amounts of AN, two recent events in Texas have put the topic of AN oversight and regulation back in the spotlight. In 2009, a chemical plant that manufactures and sells AN fertilizer caught fire in Bryan, TX. The local fire department, knowing the reactive dangers of the product, allowed the fire to burn. Over 70,000 residents from the city of Bryan and another 10,000 county residents were evacuated as a precaution. And in 2013, an explosion at another fertilizer plant in the city of West, TX, claimed the lives of 15 people, injured more than 300, and destroyed or damaged over 150 structures. Of those killed, 12 were members of the town’s volunteer fire and emergency services and were unaware of the dangers posed by a fire involving AN.(2) Following this explosion, Chemical Safety Board (CSB) chairman Rafael Moure-Eraso called for regulatory coverage of reactive chemicals.
Early agency involvement
Federal regulatory agencies and chemical industry entities have long been active in the recognition and mitigation of the hazards presented by reactive chemicals. In 1997, the Environmental Protection Agency (EPA) issued an alert in order to increase the awareness of the explosive danger of AN, and cited specific accidents to support their action. The alert stated that regulatory restrictions alone were not enough to safeguard against accidents involving the chemical.(3) It also stressed the need to safely store and handle the product in process areas, and provided information resources about AN and its hazards.(4)
Then in 2002, the CSB released a report on reactive hazards in the United States. The CSB looked at several incidents involving reactive hazards to determine, among other issues, the impacts of the incidents and how federal agencies addressed these hazards. The agency also sought to develop recommendations that would help reduce both the number and severity of reactive incidents.
The CSB concluded that neither the Occupational Safety and Health Administration (OSHA) nor the EPA clearly required reactive hazards to be examined when performing a process hazard analysis for a facility that handles those chemicals. The report’s recommendations included:
- OSHA standards should be amended so that agencies can better control reactive hazards that could cause disasters;
- The EPA should revise its accidental release prevention requirements to specifically address reactive hazards that may seriously impact the public; and
- The Center for Chemical Process Safety (CCPS) should develop and publish a comprehensive guide on model reactive hazard management systems.(5)
The CCPS responded to the recommendations by developing a guide entitled, “Essential Practices for Managing Chemical Reactivity Hazards.” The practices within can be used by facilities as a screening tool to identify chemical reactive hazards. Facilities that warehouse, repack, blend and process chemical substances are encouraged to use the process of determination offered in the guide, because it’s extremely simple, yet highly effective: Users answer a series of questions arranged on a flow chart that lead to “yes” or “no” answers.(2) The chart helps the user determine whether chemical reactive hazards are present in a facility.
The EPA followed up the CCPS’ guide with another industry alert, this time focusing on the management of already identified hazards. The practices included in this alert ask the user to complete the CCPS flow chart questions, then develop a medium to identify chemicals that react with each other. Additionally, the EPA recommended that agencies develop and train on operational procedures and hazard communications, and ensure facilities are designed or modified to include the components necessary to mitigate any hazard.(1)
Other chemical safety guidelines/programs
Other federal agencies provide regulatory oversight of hazardous materials that are not specific to chemical reactive hazards. OSHA Standard 29 CFR contains a subpart for hazardous materials that explains how to properly store AN to limit fire and detonation hazards.(6) The Department of Energy offers a chemical safety program that allows participants to share and exchange lessons learned and industry practices, and provides direction for agencies looking for chemical management strategies.(7) Additionally, the Department of Transportation provides regulatory information relating to the transportation of hazardous materials.(8)
In the aftermath of West
Since the catastrophe in West, there has been a great deal of activity on both the state and federal levels relating to the handling of AN. Four months after the blast, in the government’s ongoing effort to improve chemical risk management, the EPA, OSHA and the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) released a chemical advisory on AN, which provides:
- Information on past accidents
- Specific hazard properties of AN
- Hazard reduction steps for facilities
- Community emergency planning
- Emergency response processes
- Information resources for codes, standards and regulations for the product(9)
Then in May 2013, the Texas House of Representatives House Committee on Homeland Security and Public Safety (HSPS) released a special report regarding the regulation and monitoring of facilities that handle and store large quantities of AN. In the report, the HSPS pointed out that no particular state agency has the authority to inspect chemical facilities for issues relating to AN. The State Chemist inspects facilities that store AN, but those inspections focus on safeguarding the product, not preventing fire or explosion.
The committee further cited that local fire departments have the right to enforce local safety codes when inspecting a facility, but there is no state fire code to enhance safe facility operations and impose compliance.(10) The state fire marshal’s office responded to this by taking the following actions:
- It began a new and voluntary program that inspects facilities that store bulk amounts of AN. Note: Five facilities have turned away inspectors who requested admittance for the voluntary inspection. One railway company stated they were not interested in providing data about hazardous cargo that’s hauled by the company.1 A company representative stated that they’ve complied with existing regulations, and that the information the fire marshal was seeking is already provided to other federal and state agencies.
- They developed a website devoted to AN, tracking all facilities in the state that store more than 10,000 lbs. of AN, and keeping a list of best practices for storing the product.
- They’ve held community forums around the state where the public can hear firsthand the actions taken by officials to ensure the public’s safety in regard to these facilities.(11)
Oversight continues on all levels
Federal agencies, such as EPA and OSHA, continue to make great progress in enhancing oversight of the transportation, storage and handling of AN. Independent chemical organizations like the CSB and state agencies, such as the Texas Fire Marshal’s Office, have also continued to enhance safety recommendations through both voluntary compliance and statute. Currently, the CSB board is particularly concerned about the use of combustible wooden storage bins and buildings, and the lack of sprinkler systems that, if present, could help extinguish a fire before the product reaches an explosive capacity.
In answer to these concerns, the state fire marshal has suggested that Texas adopt national fire code standards that would require specific facilities to make structural improvements that include either the installation of fire sprinkler systems or retrofitting buildings with non-combustible materials. It was also suggested that $1.3 million be allotted to fire departments in the state so that firefighters could undergo specialized training that would better prepare them for situations involving AN and other reactive chemical hazards.(12)
More needs to be done
Whether or not more regulations from federal and state agencies will improve reactive hazard safety and awareness remains to be seen. Success depends on several things, the most important being the self-reporting and self-discipline of involved facilities. If a facility doesn’t comply with a regulation, it’s usually given a simple fine, so some facilities may choose to pay a fine if a violation is found, rather than make safety improvements; other facilities may rely on overburdened state and federal inspectors to skip site visits.
It’s been three years since the West catastrophe, and there have been no changes to any state or federal laws that would enhance reactive chemical safety and awareness. Enhanced federal regulations seem to evolve through better industry self-oversight and lessons learned.
Texas, with its vast fertilizer industry, could benefit greatly from adopting national fire code standards. In the interim, local emergency responders, along with local emergency management entities, should familiarize their organizations and communities with the specific dangers posed by reactive chemicals such as AN. As shown in the AN fire in Bryan, proper recognition and preplanning of worst-case scenarios can make all the difference in the outcome of an incident.
References
1. Environmental Protection Agency. Managing chemical reactivity hazards (EPA 550-F-04-005). www.epa.gov/oem/docs/chem/reactive-management-pub.pdf. 2005.
2. Drew, J. “Fire marshal proposes tougher rules to prevent another West.” The Dallas Morning News. May 29, 2014.
3. Environmental Protection Agency. Identifying chemical reactivity hazards: Preliminary screening method (EPA 550-F-04-004). www.epa.gov/swercepp/web/docs/chem/flowchart.pdf.
4. Environmental Protection Agency. Explosion hazard from ammonium nitrate (EPA 550-F-97-002d). 1997. www.epa.gov/osweroe1/docs/chem/ammonitr.pdf.
5. Chemical Safety Board. Hazard investigation: Improving reactive hazard management (Report No. 2001-01-H). 2002. www.csb.gov/improving-reactive-hazard-management/.
6. Occupational Safety and Health Administration. Hazardous materials: Explosives and blasting agents. www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9755.
7. Department of Energy. Chemical safety program. http://energy.gov/hss/chemical-safety-program.
8. Department of Transportation. Code of federal regulations: Title 49-transportation. www.gpo.gov/fdsys/pkg/CFR-2010-title49-vol2/xml/CFR-2010-title49-vol2-subtitleB.xml.
9. Environmental Protection Agency. Chemical advisory: Safe storage, handling, and management of ammonium nitrate (EPA 550-S-13-001). 2013. www.epa.gov/oem/docs/chem/AN_advisory.pdf.
10. Texas House of Representatives. Special report, part 1: Regarding the May 1st hearing on the West, Texas disaster. www.house.state.tx.us/members/member-page/newsletters/79/Homeland-Security-&-Public-Safety-Special-Report-Part-1.pdf. 2013.
11. Texas Department of Insurance. Ammonium nitrate in Texas. 2013. www.tdi.texas.gov/fire/fman.html.
12. Weber, P. “State fire marshal suggests new rules on storage of ammonium nitrate.” Star-Telegram. www.star-telegram.com/2014/04/14/5738286/state-fire-marshal-suggests-new.html.
