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--> Appendix B Regulation of Halon and Halon Replacements When stratospheric ozone is depleted by halons and other ozone-depleting substances, increased amounts of harmful ultraviolet radiation reach Earth's surface. Increases in UV-B radiation are likely to have substantial adverse effects on human health, including increases in the incidence of, and morbidity from, skin cancer, eye diseases, and infectious diseases.1 Peak global ozone depletion is expected to occur during the next several years, and the stratospheric ozone layer is expected to recover in about 50 years in response to international actions under the Montreal Protocol and its amendments and adjustments.2 The early phaseout of halon production accounts for at least 15% of the protection provided under the Montreal Protocol.3 The phaseout of halon production took effect January 1, 1994, with little disruption because the fire protection community had established global information networks and coordinated halon banks. Halon banks are important because environmentally acceptable alternative extinguishing agents have not been commercialized for some critical fire protection applications (15 to 20% of former uses).4,5 The success of a production ban on halons is predicated on the free exchange of existing halons, the open use of recycled halons, and a safety valve to allow for production should the banking scheme fall short of expectations (Decision IV/25 of the Montreal Protocol, which allows for continued production for ''essential'' uses). In 1985, a small group of countries signed the Vienna Convention on Ozone Layer Protection, the framework for negotiating the Montreal Protocol. In that document, halons are mentioned only briefly in an annex on monitoring of data, because earlier analysis had concluded that halon was rarely released and had predicted that halon use would decline as computer systems became smaller. In 1986, few substitutes had been identified for any of the ozone-depleting fire extinguishing substances, and it was widely believed that halon uses were all essential. It was hoped that chlorofluorocarbon (CFC) restrictions alone would adequately protect the ozone layer. By late 1986, the U.S. Environmental Protection Agency (EPA) had begun to examine the extent of halon use. The National Fire Protection Association (NFPA) planned to mandate full discharge testing of all new halon 1301 (CF3Br) systems in order to verify that the controls and hardware functioned properly and that the concentration of halon gas was high enough and remained long enough in an enclosure to extinguish a test fire. EPA was concerned that property owners, insurance companies, and fire authorities might also conclude that older systems should be discharge tested or that all systems should be periodically discharge tested. Such testing alone would have substantially increased the threat to the ozone layer. Because halons were not part of any regulatory plan and because fire protection involved human life and property, EPA officials met with the chair of the NFPA halon 1301 committee to discuss collaborative efforts to investigate halon use. It was estimated that very little halon was used to actually fight fires but that emissions from testing, training, and accidental discharge were far higher than analysts had thought. A plan was proposed to involve global experts in problem solving and to use market incentives to change the way that engineers and property owners protected against fire risk. It was agreed that EPA and the fire protection community jointly should investigate halon controls, with the goal being to act only by broad consensus. In early 1987, EPA initiated projects with the U.S. Department of Defense and U.S. Air Force. The Air Force sent a representative to Montreal to help make the case that halon should be included in the protocol. Diplomats reasoned that if the military could reduce its use, so could the civilian sector. Without this endorsement, halon production might not have been included in the 1987 Montreal Protocol.
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--> Further analysis indicated that less than 10% of halon emissions were attributable to fire fighting.6 EPA, NFPA, and other organizations were now working to educate stakeholders about the importance of eliminating testing, training, and accidental discharges. In Australia, the State of Victoria implemented strong controls on halon use, and plumbers' unions refused to install or service halon systems unless it was deemed essential by a committee of public and private experts. Elsewhere, authorities of jurisdiction were helping to eliminate requirements for discharge testing and training with halon. In 1989, the United Nations Environment Programme (UNEP) organized the first technology assessment, which included the work of the UNEP Halon Technical Options Committee. This committee of international experts became the catalyst for global efforts. Slowly fundamental change began to occur. Property owners began to use a broader range of strategies to protect property. Computer manufacturers confirmed that, contrary to advertising claims for halon, most equipment could be protected with water sprinklers. Insurance companies agreed to offer their most favorable rates to insure property with fire protection other than halon. Telecommunications companies reduced the need for halon by using cable materials that would not bum. The military began to design weapons systems that did not depend on halon. Broader fire protection engineering considerations and fire prevention began to take precedence over the basic fire-extinguishing perspective. These efforts stimulated other important paradigm shifts. For example, military aircraft designers reevaluated whether space and weight might be better allocated to threat avoidance or weapons rather than fire protection. The EPA and the Air Force helped to organize the Halon Alternatives Research Corporation (HARC) to aid in identifying the most promising research opportunities, and they worked to prepare markets to accept alternatives and substitutes as they developed. The Marine Corps, Navy, and Air Force cooperated to develop the first practical halon recycling equipment and were the first organizations in the world to deploy this equipment. The Navy and Marine Corps teamed up with EPA to teach halon recycling to experts from Latin America and the Far East. Unfortunately, halons are still required for 15 to 20% of the applications they satisfied in 1986. If halons currently contained in existing equipment are never released to the atmosphere, the integrated effective future chlorine loading above the 1980 level is predicted to be 10% less over the next 50 years.7 See Chapter 3 for further discussion. Thus, much work remains to complete the phaseout of halon use. Chemical substitutes for halon for the remaining important uses are a part of the ultimate solution. U.S. Regulation of Halons and Halon Substitutes When the Montreal Protocol was signed in 1987, the EPA's role in stratospheric ozone protection derived from the Clean Air Act of 1977, Part B, section 157(b): . . . the Administrator shall propose regulations for the control of any substance, practice, process or activity (or any combination thereof) which in his judgment may reasonably be anticipated to affect the stratosphere, especially ozone in the stratosphere, if such effect in the stratosphere may reasonably be anticipated to endanger public health or welfare. This language gave EPA broad latitude, but it did not give clear guidance. EPA began to develop control strategies based primarily on measures of ozone depletion potential (ODP). A product whose ODP was lower than that of the CFCs was considered to have an advantage over the halons. Thus, FM-100™ (HBFC-22B1 or CF2HBr) with an ODP of 0.748 was investigated as an effective halon substitute. With the enactment of the Clean Air Act Amendments of 1990 (CAAA), Congress provided guidance to EPA by stipulating that any substance with an ODP of 0.2 or greater would be a class I substance and would be subject to the same production phaseout as the CFCs and halons. This restriction effectively eliminated some potential fire-extinguishing substitutes, such as FM-100™, and mixtures using CFCs.
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--> Title VI of the U.S. Clean Air Act of 1990 enacts the U.S. strategy for complying with the Montreal Protocol for protection of Earth's stratospheric ozone layer.9 Title VI is administered by the Stratospheric Protection Division within the Office of Air and Radiation. Section 612 of Title VI directs EPA to set up the Significant New Alternatives Policy (SNAP) program, to evaluate any halon substitutes or alternative fire protection technologies to ensure that they reduce the overall risk to human health and the environment and to promote these substitutes to achieve rapid market acceptance. EPA's goal is to ensure that industry and consumers have ample choices for the diversity of applications in which CFCs and halons are currently used. EPA adopted a risk-balancing approach on health and safety issues by looking at likely exposure pathways in use of a substitute agent in each sector. The risk to individuals from exposure to halon substitutes is generally from discharges that occur infrequently. Chronic effects from exposure to halon substitutes are not usually a concern, because when used, these substances are discharged in high concentrations over short periods of time and thus potentially present an acute hazard. Risk from exposure to halon substitutes is accordingly best assessed by analysis of acute toxic effects associated with exposure to these compounds, such as developmental toxicity and cardiotoxicity. In most instances, cardiotoxicity occurs at lower levels than does fetotoxicity, and therefore, unless otherwise warranted by the developmental data, EPA bases the estimates for emergency exposure limits during halon use on the no observable adverse effect level (NOAEL) and lowest observable adverse effect level (LOAEL) reported for epinephrine-sensitized cardiotoxicity in dogs (and in a few instances monkeys). Human heart arrhythmias and sudden death resulting from overexposure to CFCs, halons, and other halogenated and non-halogenated hydrocarbons have been documented in work-place settings and in volatile substance abuse (e.g., glue sniffing).10 To assess the safety of a fire extinguishing agent for use in a total flooding system, EPA analysts examine the actual design concentration as NFPA defines it,11 i.e., the cup burner extinction concentration plus 20%, or in some cases the actual large-scale testing design concentration, and compare this value to levels at which cardiotoxic effects have been observed. The situation differs for streaming agents (i.e., chemicals applied to localized fires, usually by being propelled from an extinguisher) because such use is a localized application, and air exchange further dilutes the concentration of the agent. EPA requires manufacturers to submit data acquired by personal monitoring for the anticipated usage. The results of these tests show that actual exposure is much lower than what the models predict. Consequently, EPA has listed agents as acceptable, even with a LOAEL as low as 1.0 or 2.0%.12 The conditions stipulated under SNAP for use of total flooding agents are patterned after current Occupational Safety and Health Administration (OSHA) requirements for use of halon 1301 (CF3Br) systems. Because OSHA does not currently specify acceptable levels of exposure to substitute fire extinguishing agents, EPA is laying these values out very specifically and has initiated efforts to work with OSHA as that agency takes steps to amend its regulation of fixed gaseous extinguishing systems (OSHA Regulation 1910.162). When considering environmental effects of halon substitutes, EPA first looks at ozone depletion potential to determine if a substance could significantly damage the stratospheric ozone layer. Any class I substance (ODP of 0.2 or higher) must be phased out of production in the United States within 7 years of listing. While the Clean Air Act does not explicitly define a class II substance, by implication it is an agent with an ODP of less than 0.2. Currently the chemical with the lowest ODP that EPA has listed as a class II substance is HCFC-123 (CF3CHCl2), with an ODP of 0.02. While EPA considers other environmental impacts besides ozone depletion potential (including aquatic toxicity, air pollution, and so on), global warming potential (GWP) and atmospheric lifetime are the key additional issues in evaluating halon substitutes. Action number 40 of President Clinton's Climate Change Action Plan, released in November 1993, directs EPA to minimize unnecessary emissions of greenhouse gases to help meet the national goal of reducing emissions in the year 2000 to 1990 levels. EPA again has adopted an approach that seeks to balance the risk posed by ODP and GWP and the related atmospheric lifetimes of these agents.
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--> The CAAA directs EPA to "reduce overall risks to human health and the environment."13 EPA has attempted to characterize emission levels and exposure pathways in each use sector in order to minimize environmental impacts. Thus, EPA first looks for the outliers such as the perfluorinated carbons (PFCs), which have atmospheric lifetimes in excess of 3,000 years and are virtually indestructible.14 Yet, because PFCs have a favorable toxicity profile, EPA recognizes that they can play a role in fire protection applications where other agents are not suitable for either technical or safety reasons. Thus, EPA has listed PFCs as acceptable with certain contingent restrictions. Likewise, although HFC-23 (CF3H) has a 300-year lifetime,15 it is a by-product of the manufacture of HCFC-22 (CF2HCl), which will continue to be produced as an intermediate for the manufacture of polymers such as Teflon™, and EPA thus has placed no restriction on its use as a fire protection agent. In response to concerns about environmental effects and efficacy, fire protection manufacturers are also developing several new alternative fire protection technologies, including inert gas systems, water mist systems, and powdered aerosol systems. These non-halocarbon alternative agents require a different means of determining risk during use. Some of the newer non-halocarbon alternative agents—the inert gas systems—limit but do not entirely remove the oxygen available to a fire. The most important condition for the safe use of such agents is the stipulation that the amount of oxygen remaining in the area of release is sufficient to maintain central nervous system function and that reduced oxygen does not impair escape from the area if people are exposed. Powdered aerosol systems present still other risk assessment issues. The conditions determining the safe use of these agents must account for potential deposition in the respiratory tract of inhalable particles, ranging from very small particles that may be deposited in the alveoli to large particles capable of irritating the upper nasal passages. The size of such particles may be the most significant factor determining risk. Water mist systems using pure water pose little risk, although additives must be evaluated on a case-by-case basis to determine potential health hazards. A concern with both mist and powdered aerosol systems is the visual obscuration that occurs during discharge and that may potentially limit individuals' ability to leave the area. Because the risk analyses for alternative fire protection technologies differ somewhat from standard EPA risk assessment procedures, EPA has encouraged the formation of ad hoc workshops and medical peer-review panels to characterize the risks presented by each new technology and to help delineate the appropriate exposure limits for different clinical groups. Conditions for the appropriate use of inert gases with limited oxygen have been evaluated by special medical panels, and EPA has also solicited guidance from OSHA on conditions of use, since OSHA will ultimately determine the proper use of all fire suppressant systems. Workshops and panels have been formed to analyze issues concerning powdered aerosols and water mists. Alternatives to Use of Halons The EPA has been largely successful in identifying several agents and technologies that can be used in most total flooding and streaming fire protection applications. There are still some application areas that pose technical challenges, however, including aviation (both civil and military), military tanks, some military shipboard uses, and explosion inertion applications. The U.S. military has been a leader in research and development efforts, e.g., the selection of HFC-125 (CHF2CF3) for the design of fire protection systems on new military aircraft and the selection of HFC-227ea (CF3-CHFC-CF3; or FM-200™) for new shipboard machinery spaces. For commercial aircraft, the Federal Aviation Administration (FAA) is spearheading an industrywide R&D effort to identify effective substitutes for halon as a fire suppressant. Once an agent is identified for complex systems, much work still remains to design, manufacture, and certify the fire protection system (see Chapters 1 and 2 for details).
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--> Halon Bang To serve existing applications depending on equipment that cannot be retrofitted cost-effectively, the U.S. EPA encourages halon banking programs. The Department of Defense maintains such a bank for mission-critical systems, managed by the Defense Logistics Agency, which also serves as the buffer needed while new agents are identified and systems developed for new platforms. In the commercial sector, users have undertaken similar actions to redeploy and bank halon. Private-sector businesses have sprung up to work the halon recycling market, and the non-profit Halon Recycling Corporation plays an important role in aiding buyers and sellers of halon both in the United States and abroad. The data for estimating the global supplies of halons are collected by two different methods. The first is based on amounts manufactured annually by the major producers and on emission patterns. Countries that have required collection of halon for destruction provide the second. In two such countries, Australia and Germany, the first estimates of the halon to be collected were based on the study of annual production. In both cases, these initial estimates had to be revised downward because the actual quantity of halons collected fell short of projections, possibly because (1) actual quantities within the country were less than estimated, (2) some halon was emitted rather than being collected, or (3) the halon was not turned in. Any or all these could account for the discrepancies. The major point is that we just do not know. Currently, UNEP's Halon Technical Options Committee is reexamining its estimates of the global bank of halons. References 1. J.D. Longstreth et al., "Effects of Increased Solar Ultraviolet Radiation on Human Health," pp. 23-48 in Environmental Effects of Ozone Depletion: 1994 Assessment , J.C. van der Leun, Ed., United Nations Environment Programme, Nairobi, Kenya, November (1994). 2. S. Solomon, D. Wuebbles, et al., "Ozone Depletion Potentials, Global Warming Potentials, and Future Chlorine/Bromine Loading," pp. 13.9-13.13 in Scientific Assessment of Ozone Depletion: 1994, Co-Chairs, Daniel L. Albritton, Robert T. Watson, and Piet J. Aucamp, World Meteorological Organization, Geneva (1994). 3. U.S. Environmental Protection Agency, Risk Screen on the Use of Substitutes for Class I Ozone Depleting Substances: Fire Suppression and Explosion Protection, EPA, Washington, D.C., March (1994), pp. 2-2 to 2-4. 4. Gary Taylor, "Halon Bank Management - A Rationale to Evaluate Future World Supplies," in Proceedings of the Second International Conference on Halons and the Environment, CFPA Europe/NFPA, Geneva, Sept. 28 (1990). 5. Environment Canada, Halon Bank Management—A Rationale for Canada , March 15 (1990). 6. Halon Fire Extinguishing Agents Technical Options Report to the United Nations Environment Programme Technology Review Panel, Gary Taylor and Major E. Thomas Morehouse, Jr., Co-Chairs, Toronto, Canada, June (1989), p. 9. 7. S. Solomon, D. Wuebbles, et al., "Ozone Depletion Potentials, Global Warming Potentials, and Future Chlorine/Bromine Loading," pp. 13.9-13.13 in Scientific Assessment of Ozone Depletion: 1994, Co-Chairs, Daniel L. Albritton, Robert T. Watson, and Piet J. Aucamp, World Meteorological Organization, Geneva (1994). 8. Ozone Secretariat, Handbook for the Montreal Protocol on Substances That Deplete the Ozone Layer, third edition, United Nations Environment Programme, Nairobi, Kenya, August (1993), p. 27. 9. Clean Air Act, U.S. Code, Vol. 42, Title VI, secs. 7450 et seq. (1990). 10. Reva Rubenstein, "Human Health and Environmental Toxicity Issues for Evaluation of Halon Replacements," Toxicology Letters 68, 21-24 (1993). 11. National Fire Protection Association, Halon 1301 Fire Extinguishing Systems, NFPA 12A, NFPA, Quincy, Massachusetts (1992), pp. 12A-11. 12. U.S. Environmental Protection Agency, Significant New Alternatives Policy Program, Rulemakings, and Notices, 59 FR 13044 (March 18, 1994); 59 FR 44240 (August 26, 1994); 60 FR 3318 (January 13, 1995). 13. Clean Air Act, U.S. Code, Vol. 42, Title VI, secs. 7401 et seq., sec. 612(a) , (1990). 14. A.R. Ravishankara, S. Solomon, A.A. Turnipseed, and R.F. Warren, "Atmospheric Lifetimes of Long-lived Halogenated Species," Science 259, 194-199 (1993). 15. Du Pont Fluorochemicals, "EPA SNAP Submission for HFC-23," January (1993).
Representative terms from entire chapter: