Regulating halon emissions

The global community has made great strides in preserving the ozone layer. But we're not out of the woods yet.

The halon community is taking a proactive response to the depletion of the Earth's stratospheric ozone layer, which shields life on the surface from harmful ultraviolet-B radiation (UV-B). In fact, some consider this response to be a case study in successful collaboration among industry, the military, end-users, and regulators in addressing great challenges to achieve a pressing global environmental objective.1

Halons are gaseous or easily vaporized halocarbons used primarily to extinguish fires, although they also can be used for explosion protection. In the United States, the two most common halons are Halon 1211 and Halon 1301. Halon 1211 is used in streaming applications and, at its peak, was a nearly ubiquitous streaming agent.2 Currently, the military and equipment distributors use recovered Halon 1211 to fill or recharge portable fire extinguishers, and some is stockpiled and resold by commercial recycling facilities.3

Halon 1301 is typically used in total-flooding applications. At one time, Halon 1301 total-flooding systems for occupied areas were the most efficient and popular fire suppression systems of their kind. Today, the market for recovered Halon 1301 is driven largely by servicers of halon fire protection systems, the military, and large commercial interests, including airlines. System servicers use recovered Halon 1301 to recharge systems, stockpile it for future sale, sell it to other servicers, or sell it to military or commercial interests.

Another type of halon-Halon 2402-is used very little in the United States. Although it's an effective fire extinguishing agent, its use in North America and Europe has been greatly limited by concerns about its safety.4 However, it continues to be used in the Russian Federation and in other countries with economies in transition.5

Halons are used in a wide range of fire protection applications because they combine four characteristics. First, they're highly effective against solid, liquid/gaseous, and electrical fires, which are referred to as Class A, B, and C fires, respectively. Second, they dissipate rapidly, leaving no residue, thereby preventing secondary damage to the property they're protecting. Third, halons don't conduct electricity and can be used in areas containing live electrical equipment, where they can penetrate and surround objects to extinguish fires in otherwise inaccessible areas. Finally, halons are generally safe for use around people when the proper exposure controls are in place.

Despite these advantages, halons are among the most ozone-depleting chemicals in use today. Stratospheric ozone shields the Earth's surface from dangerous ultraviolet radiation. As ozone disappears, UVB radiation will increase, causing an increase in certain skin cancers and cataracts, suppression of the immune response system, and damage to crops and aquatic organisms. When compared to CFC-11, a widely used refrigerant with an ozone-depleting potential (ODP) of 1, Halon 1301 has an estimated ODP of 10, and Halon 1211 has an estimated ODP of 3. Thus, while total halon production, as measured in metric tons, comprised just 2 percent of the total production of Class I substances in 1986, halons represented 23 percent of the total estimated ozone depletion attributable to Class I substances produced during the same period.

The Clean Air Act (CAA) established two classes of ozone depleting substances (ODSs). Class I ODSs include all chlorofluorocarbons (CFCs) and halons, carbon tetrachloride, methyl chloroform, and other substances determined to have an ODP of 0.2 or greater. Class II ODSs include HCFCs, as well as other substances found to cause or contribute to harmful effects on the stratospheric ozone layer. The Montreal Protocol, a landmark international environmental agreement first negotiated in 1987 that now involves more than 162 countries, limits the depletion of the stratospheric ozone layer by eliminating or drastically reducing new production of ODSs globally, including CFCs and halons.

Halon practices in the United States

During the early stages of international concern about stratospheric ozone depletion, members of the U.S. halon community began to investigate opportunities to reduce halon emissions. As early as 1987, for example, United States Air Force researchers sponsored simulations of methods for reducing the need for halons during firefighter training and examined how new equipment could be used to recycle halon, rather than vent it to the atmosphere.6

At the same time, the North American fire protection community launched a number of voluntary steps to reduce nonessential halon emissions. Members of the community studied and quantified applications and releases of halons, re-examined the need for discharge testing of halon systems, and participated in conferences and other initiatives to educate their constituencies on reducing unnecessary releases of halons.7 In the early 1990s, several initiatives helped ensure that the 1994 phaseout of halon production in the developed world was technically and economically feasible. These include establishing the Halon Alternatives Research Corporation, an information clearinghouse and trade association for parties interested in alternatives to halons; developing halon recycling capabilities; and establishing the Halon Recycling Corporation, an organization that matches sellers of excess halon to buyers.

U.S. halon recycling and emission reduction regulation

A heightened concern about stratospheric ozone layer depletion, combined with the increased economic value of halons, limited the need for additional domestic regulation of the fire protection industry to further reduce halon emissions.

Nevertheless, the Sierra Club, a nonprofit, member-supported conservation organization, filed a complaint against the U.S. Environmental Protection Agency (EPA) in 1995, claiming EPA hadn't met the requirements of a section of the CAA, as amended in 1990, requiring the agency to issue regulations to reduce halon emissions to their lowest achievable levels and to maximize their recapture and recycling. As part of a settlement subsequently agreed to by the Sierra Club and EPA, EPA examined the possibility that further reductions could be achieved through regulation. In 1998, EPA issued a rule that essentially codified and more fully extended the environmentally responsible halon handling already widely practiced in the fire protection community

This rule, 63 FR 11084, published March 5, 1998, otherwise known as the "March 5th Rule," sought to ensure environmental benefits by requiring a set of practices, already widely adhered to, that would minimize unnecessary releases of halons. First, the rule banned creating blends of halons on the grounds that the infrastructure to recycle and reuse such blends isn't generally available and that growing stocks of nonrecyclable halon blends would pose a significant environmental risk. Furthermore, the rule prohibited the venting or intentional release of halons during most technician training exercises, or during other activities such as the testing, repair, or disposal of halon-containing equipment. The rule also required that technicians who work with halon-containing equipment be trained about halon emissions reductions. Finally, the rule required that halons and halon-containing equipment be "properly disposed of." That is, the only permissible means of disposing of halon and haloncontaining equipment, aside from destruction, are by recovering the halon with minimal losses to the atmosphere and by recycling it using facilities that operate in accordance with NFPA 10, Portable Fire Extinguishers. In addition, acceptable destruction technologies were limited to several controlled processes identified in the regulation.

In recognition of the special needs of certain critical halon applications, the rule provided for some exemptions. For example, the release of halons during the testing of fire extinguishing systems or equipment is exempted if four criteria are met: systems or equipment using suitable alternative agents aren't available; system or equipment testing requiring the release of the agent is essential to demonstrate system or equipment functionality; system failure would pose great risk to human safety or the environment; and a simulant agent can't be used for testing purposes. In addition, releases associated with qualification and development testing during the design and development of halon-containing systems and equipment are exempted, but only when such tests are essential to demonstrate functionality and a suitable simulant agent can't be used for testing purposes. Certain releases during research and development for halon alternatives and during analytical determination of halon purity are also exempted.

As part of the settlement with the Sierra Club, EPA agreed to consider whether it would be necessary and appropriate under Section 608 of the CAA to establish a program to certify halon recovery and recycling equipment, based on its ability to minimize losses of halons to the atmosphere, and to require that halon recovery and recycling only be done using certified equipment. In 1998, EPA examined the need for, and potential environmental benefits from, such a program. The study, which was reviewed by technical and scientific experts from industry, academia, and government, as well as by other stakeholders, suggested that the great majority of halon recovery and recycling equipment currently in use or on the market consists of highly efficient halon closed recovery systems that achieved a minimum recovery efficiency of 98 percent. And the organizations that perform the vast majority of halon transfers employ these efficient units.

In 1997, the latest year for which data were available for the study, it was estimated that of the 27,000 tons (24,493.97 metric tons) of Halon 1211 and 17,000 tons (15,422.13 metric tons) of Halon 1301 that constitute the North American halon "stock," approximately 1,080 tons (976.76 metric tons) of Halon 1211 and 790 tons (716.68 metric tons) of Halon 1301 were released in the United States for all purposes, both firefighting and inadvertent discharges. Approximately 1 percent of these releases, it was estimated, were attributable to operations using less efficient halon recycling and recovery equipment and methods. Furthermore, the March 5th Rule established that halon recovery and recycling can only be performed by facilities operating in accordance with NFPA 10, thereby establishing that halon recovery must occur with only minimal losses to the atmosphere.

On these grounds, EPA determined that it was neither necessary nor appropriate to issue a rule under CAA Section 608 establishing a certification program for equipment used in the recovery and recycling of halons or to require that halons be recovered only through the use of certified equipment. In August 1998, EPA published a determination to this effect in the Federal Register, 63 FR 42728. It should be noted that the August determination doesn't affect the existing legal requirements regarding halons established under the March 5th Rule.

Halon alternatives

Another major element of EPA's strategy to protect the stratospheric ozone, as directed by the CAA, has been the establishment of the Significant New Alternatives Policy (SNAP) program. The first SNAP rulemaking, which describes the process for administering the SNAP program and contains EPA's first acceptability lists in the major industrial use sectors, including fire suppression and explosion protection, was published in 1994. According to Section 612 of the CAA, EPA was to establish a program to evaluate any substitute substance or alternative technology that would replace a Class I or Class II ODS in order to ensure that the substitutes reduce the overall risk to human health and the environment, and to promote these substances to achieve rapid market acceptance. The SNAP program fulfills this mandate.

EPA's goal under this program is to ensure that industry and consumers have ample alternatives for the range of applications for which CFCs, halons, and other ODSs are currently used. SNAP establishes that Class I and Class II ODSs may not be replaced by any substitute that EPA has determined may present adverse effects to human health or the environment if an alternative that reduces overall risks to human health and the environment has been identified and is available.

In evaluating new substitutes, EPA requires the submission of information covering a wide range of properties, such as physical and chemical characteristics, ODP, global warming potential (GWP), human health toxicity, flammability, applications, process description, environmental fate and transport data, and cost information. EPA then examines the health and safety risks by exploring the use of each agent under likely exposure. In balancing environmental and health considerations, EPA assesses the full spectrum of data pertaining to toxicological risks, ODP, GWP, the atmospheric lifetime of the agent, and other environmental criteria, such as aquatic toxicity Although suitable alternatives haven't been found for some critical halon firefighting applications, including some commercial aviation fire protection needs and some military applications, the SNAP program has listed several acceptable agents and technologies for total-flooding and streaming applications.

Progress and outlook

The Montreal Protocol and its amendments ultimately are responsible for preserving the Earth's stratospheric ozone layer. According to the current scientific assessment of the ozone layer, today's surface UV-B radiation would have been at least 100 percent higher than it was before 1980 at mid-latitudes in the Northern Hemisphere if international agreements to limit production and emissions of ODSs hadn't been signed.8 In the Southern Hemisphere mid-latitudes, LTV-B radiation would have been 400 percent higher. Instead,, increases in surface UVB radiation are limited to 5 percent in the Northern Hemisphere and 8 percent in the Southern Hemisphere.

Although the ozone layer is currently at its most vulnerable because concentrations of ODSs are at peak levels, these levels have, in many cases, plateaued or begun to drop. Full recovery of ozone in the stratosphere isn't expected until approximately 2050, assuming the international community continues to comply with these agreements. Somewhat more rapid recovery of stratospheric ozone could occur if the international community pursued the few remaining control options-for example, complete cessation of the production of ODSs and contained destruction of all existing ODSs deployed in equipment. Even a combination of these measures could achieve only an accelerated restoration of one to three years, however, and the cost would be enormous.

Despite the considerable success of the Montreal Protocol, several challenges remain. Although CFC and halon production in the developed world ended in 1994, production of these substances will continue in the developing world until 2010. A thriving illegal trade in ODSs has arisen. In Miami, for a time, it was thought that only cocaine had more street value than CFCs. Globally, illegal trade in CFCs amounts to 20,000 tons (18,143.68 metric tons) a year. Even in 1995, before the total CFC phaseout, chemical firms estimated that up to 20 percent of all CFCs in use had been bought on the black market.910 Furthermore, Australian and British researchers recently found that global emissions of Halon 1211 are greater than previously supposed. And in contrast with most CFCs, whose atmospheric concentrations are either steady or falling, Halon 1211 emissions appear to be rising. Researchers note that halons currently are estimated to account for 20 percent of global ozone destruction.

On the other hand, there's very positive news. China, the world's largest producer of halons, has been working with the Multilateral Fund of the Montreal Protocol and has announced that it will be able to reduce halon production significantly ahead of schedule.

1 Andersen, S. O., Metchis, K. L., and Rubenstein, R., 1995. "The History of the Halon Phaseout and Regulation of Halon Alternatives," Chapter 2, Halon Replacements: Technology and Science, American Chemical Society (ACS) Symposium Series 611, ACS, Washington, D.C.

2 Seaton, M., 1995, "Halon: Searching for Solutions," NFPH Journal, November/December, 1995, pp. 47-53.

3 EPA, 1998b, Direct final determination published as 63 FR 42728, "Protection of Stratospheric Ozone: Halon Recycling and Recovery Equipment Certification."

4. UNEP, 1994, "Montreal Protocol on Substances that Deplete the Ozone Layer-Report of the Halon Fire Extinguishing Agents Technical Options Committee," December 1994, UNEP Ozone Secretariat, Nairobi, Kenya, p. 174.

5. UNEP, 1998a, "Montreal Protocol on Substances that Deplete the Ozone Layer-Technology and Economic Assessment Panel," April 1998 Report, UNEP Ozone Secretariat, Nairobi, Kenya.

6. Cook, E., 1996, "Battling Halons," Chapter 7, Ozone Protection in the United States, World Resources Institute, Washington, D.C., p. 120.

7. Grant, C. C., 1994, "Halon and Beyond: Developing New Alternatives," NFPA Journal, November/December 1994, pp. 41-54.

8. UNEP, 1998b, "Executive Summary: Scientific Assessment of Ozone Depletion," 1998.

9. "Holed Up," The Economist, 12/9/95, p. 63.

10. "Phew, the Ozone Layer May be Saved," The Economist, 9/13/97, p. 48.

Lisa Chang is a staff member of EPAs Stratospheric Protection Division, which is responsible for all EPA programs related to protecting the ozone layer.

Copyright National Fire Protection Association Jul/Aug 1999
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