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Statement of Need: Under the Clean Air Act (CAA) Amendments of 1990, EPA is required to establish National Emission Standards for Hazardous Air Pollutants (NESHAPs) for most hazardous waste combustors (HWCs) (i.e., incinerators, cement kilns, boilers, and some types of smelting furnaces). In addition, under the Resource Conservation and Recovery Act (RCRA), EPA is required to establish standards for all HWCs as necessary to ensure protection of human health and the environment. EPA is concerned that its current RCRA standards for HWCs may not be adequately protective given that the standards do not take into account indirect pathways of exposure and that there have been advances both in risk assessment and control technologies since promulgation of the current standards. ^PConsequently, the Agency plans to establish new emissions standards for HWCs under joint CAA and RCRA authority. This will avoid duplicative Agency effort and piecemeal regulation of the hazardous waste combustion industry.

Alternatives: Under provisions of the CAA, the Agency plans to consider the cost-effectiveness of emission limits more stringent than the minimum limits mandated by the statute. Further, the Agency plans to evaluate approaches to reduce emissions of hazardous air pollutants by improving good operating practices (e.g., controlling the way in which problematic materials such as toxic metals are introduced into the combustor).

Anticipated Costs and Benefits: EPA's analysis of the recommended standards for the final rule indicate that some combustion facilities may experience a substantial change in the per ton cost of burning waste, but that this change is likely to have a limited impact on the overall combustion market. In terms of effects on waste-burning cost structure, cement kilns and lightweight aggregate kilns (LWAKs) are most affected by the regulation. This is primarily a product of their relatively low baseline costs of burning, meaning that incremental compliance costs represent a large increase in their overall cost of burning waste. For incinerators, compliance costs are lower, represent smaller additions to baseline costs, and change little across regulatory options. The analysis concludes that cement kilns have the lowest waste burning costs even after regulation, and so will continue to have the greatest flexibility in marketing their services. ^PTo the extent that compliance costs cannot be passed through to generators and fuel blenders, the profitability of waste burning in kilns will fall. Nonetheless, waste burning kilns are expected to have healthy operating profit margins after the rule. Market exit in all sectors is concentrated among facilities that burn small quantities of hazardous waste. Approximately 15 combustion facilities may stop burning hazardous wastes as a result of the planned maximum achievable control technology (MACT) options. The small quantities these facilities burn suggest that market dislocations will be minor. ^POverall, the social costs of the rule are balanced by a set of potentially substantial benefits. Given the severity of the potential adverse health effects from dioxin and mercury (cancer, adverse developmental effects in children, severe neurological effects in adults, and bioaccumulation in ecosystems), EPA believes the substantial reductions of these pollutants from hazardous waste burning sources under the MACT standard justifies moving ahead with the final recommended standards.

Risks: EPA has estimated that hazardous waste incinerators and hazardous-waste burning cement and lightweight aggregate kilns currently emit (1997 base year) a total of 40g toxicity equivalent (TEQ) of TCDD and TCDF (isomers of dioxin) per year. Therefore, hazardous waste burning sources represent about 1.5 percent of total anthropogenic emissions of dioxins in the U.S. ^PEPA estimates that dioxin emissions from hazardous waste-burning sources will be reduced to approximately 12g TEQ per year at the recommended standard. These reductions would result in decreases to approximately 0.4 percent of total estimated anthropogenic U.S. emissions. EPA expects that reductions in dioxin emissions will help reduce dioxin levels over time in foods used for human consumption and, therefore, reduce the likelihood of adverse health effects, including cancer, occurring in the general population. ^PEPA has estimated that hazardous waste incinerators and hazardous waste-burning cement and lightweight aggregate kilns currently emit a total of 6Mg of mercury per year. Based on these estimates, hazardous waste-burning sources represent about 4.4 percent of total anthropogenic emissions of mercury in the U.S. ^PEPA estimates that mercury emissions from hazardous waste-burning sources will be reduced to 2.3Mg per year at the current floor levels. These reductions would result in reductions of total anthropogenic U.S. emissions to approximately 1.6 percent. EPA expects that reductions in emissions from mercury-emitting sources will help reduce mercury levels in fish over time.