Under the Clean Air Act, the Environmental Protection Agency (EPA) sets National Emissions Standards for Hazardous Air Pollutants, or NESHAPs. These emissions standards limit the amount of hazardous air pollutants (HAPs) entering the ambient air in order to protect public health and the environment. Some examples of HAPs are asbestos, benzyl chloride, chlorine and formaldehyde.

Section 112 of the Clean Air Act requires that the EPA list hazardous air pollutant sources and establish nationwide technology-based emission standards for these sources. Major stationary sources require the most stringenttechnology-based pollution control called Maximum Achievable Control Technology (MACT). For area sources, EPA requires generally available control technology (GACT), which is less stringent than MACT.

NESHAPS in Arizona

In some instances, the authority to implement and enforce NESHAPs is delegated to states or other local agencies. In Arizona, ADEQ enforces NESHAPs through its permitting program. NESHAPs delegated to local air quality agencies are in the Code of Federal Regulations (CFR), Title 40, Parts 61.04 and 63.99.

Examples of sources regulated under NESHAPs in Arizona are:

  • Asbestos in sources such as insulation, roofing and paint
  • Dry cleaning facilities
  • Glass manufacturing plants
  • Primary copper smelting
  • Wood furniture manufacturing

New Source Performance Standards

Clean Air Act Section 111 requires that the EPA set nationwide uniform technology-based emission standards for new or modified stationary sources. These New Sources Performance Standards (NSPS) apply not only to newly constructed sources, but also to modifications of existing sources that cause an increase in emissions or a change in the types of emissions.

Some examples of these sources are coal-fired power plants, petroleum refineries, landfills and boilers. The EPA develops and revises a list of source types that fall under NSPS. Sources categorized under NSPS must monitor and test their emissions and comply with numerical emission limitations.

NSPS in Arizona

The EPA may delegate its authority to enforce NSPS to states and other local agencies. A complete list of sources subject to NSPS and delegated to Arizona can be found in 40 CFR Section 60.4.

Examples of NSPS sources in Arizona are:

  • Fossil-fuel fired steam generators
  • Portland cement plants
  • Nitric acid plants
  • Primary copper smelters
  • Stationary compression ignition internal combustion engines