The U.S. Environmental Protection Agency (EPA) continues to send mixed messages regarding whether and to what extent air emissions should be taken into account when determining whether materials are wastes for purposes of the Clean Air Act (CAA). While one might assume that air emissions are relevant given the CAA context, that is not necessarily the case, which makes some sense because the determination should focus on whether a material is a “waste” or not. EPA’s “non-hazardous secondary materials” (NHSM) criteria under 40 C.F.R. part 241 are intended to help prevent “sham” recycling of wastes, and EPA has focused in large part on contaminants found within the material itself, and regardless of the CAA-related purpose, EPA has tended not to consider air emissions resulting from the combustion of the fuel. Despite EPA’s general approach and numerous statements to the contrary during the rulemaking process, EPA sometimes takes air emissions into account, although inconsistently. For example, in recent “comfort letters” implementing the NHSM rule, EPA compares contaminants in the NHSM to traditional fuels but also indicates that air emissions can indeed play an important role in waste determinations. This article explores EPA’s stated goals for the NHSM rule and the role air emissions have played in solid waste determinations under section 129 of the CAA.
Laudably, Congress intended the CAA to improve air quality, promote public health, and prevent and control air pollution. Section 101(a), CAA. Prior to the CAA Amendments of 1990, EPA relied on CAA Sections 111 (New Source Performance Standards or NSPS) and 112 (National Emissions Standards for Hazardous Air Pollutants or NESHAP) to regulate sources of air emissions that may adversely affect human health and welfare. Under that authority, EPA first regulated municipal waste combustors in the early 1970s and in the mid-1980s established particulate matter standards for industrial, commercial, and institutional steam-generating units burning municipal waste.
In response to public concerns regarding solid waste incineration, Congress added section 129 as part of the 1990 CAA Amendments. This new provision required that EPA regulate all categories of nonhazardous waste incinerators, including not only those combusting municipal waste but other categories as well (collectively referred to as “incinerators”) pursuant to sections 111 and 129. The statutory language also clarified that units subject to emission standards under section 129 would not be subject to emission standards under section 112. Specifically, EPA must establish numeric emission limits for four criteria pollutants: particulate matter, sulfur dioxide, nitrogen oxides, and carbon monoxide, as well as five hazardous air pollutants: hydrogen chloride, cadmium, mercury, lead, and dioxins/dibenzofurans. EPA also has the discretion to establish standards, as appropriate, for other regulated air pollutants. While combustion sources are regulated under section 111 and either section 112 or 129, the type of fuel being used and whether it is considered “waste” will determine which set of standards apply.