National Emission Standards for Hazardous Air Pollutants (NESHAP)
The Clean Air Act requires the U.S. Environmental Protection Agency to regulate emissions of toxic air pollutants, called Hazardous Air Pollutants (HAPs), from facilities that emit one or more of these pollutants in significant quantities. The resulting regulations are known as National Emission Standards for Hazardous Air Pollutants (NESHAP).
There are two types of NESHAPs: major source area source. Minnesota is a delegated authority for major source NESHAPs, which means the MPCA incorporates major source standards into facility permits and enforces the requirements. Minnesota does not have delegated authority for area source NESHAPs, which are enforced by the U.S. EPA.
NESHAPs are an additional federal standard beyond an air permit, so even if your business already has an air permit, you may need to meet the additional requirements of a NESHAP. Due to the number and variety of NESHAPs, it is likely that one or more apply to your business.
To find a complete list of major and area source NESHAPs, click on the “EPA's List of National Emission Standards for Hazardous Air Pollutants (NESHAP)” below.
The MPCA's Small Business Environmental Assistance Program can help you determine if a NESHAP applies to your business, complete the appropriate notification forms, and comply with the standard. Please call the SBEAP hotline at 651-282-6143 or 800-657-3938 if you have questions.
- Area source facilities are those whose potential emissions are below 10 tons per year of a single hazardous air pollutant or 25 tons per year of any combination of hazardous air pollutants.
- Area source NESHAPs are the specific group of standards that apply to area sources. The area source NESHAPs apply to emission activities at area sources, and require applicable sources to follow GACT standards (Generally Available Control Technologies). The MPCA is not a delegated authority for area source NESHAPs; they are enforced by the EPA.
- Criteria pollutants are seven pollutants (carbon monoxide, lead, nitrogen oxide, ozone, particulate matter with diameters of 10 micrometers or less (PM 10), particulate matter with diameters of 2.5 micrometers or less (PM 2.5), and sulfur dioxide) determined by the US EPA to be hazardous to human health. The term "criteria pollutants" comes from the requirement that EPA must describe the characteristics and potential health and welfare effects of these pollutants. It is on the basis of these criteria that air quality standards are established.
- Delegated authority is the term given to a local agency when the EPA delegates its regulatory authority to administer a regulation. It is through the delegation of authority that the MPCA can implement and enforce federal regulations.
- Hazardous air pollutants (HAPs) are specific chemicals and materials that have been determined to be hazardous to human health or the environment. They were initially listed in 1990, in Section 112 of the Clean Air Act.
- Major source facilities are those with a potential to emit (PTE) more than 10 tons per year of a single hazardous air pollutant or 25 tons per year of any combination of hazardous air pollutants.
- Major source NESHAPs are the specific group of standards that apply to major sources. The major source NESHAPs apply to emission units at major sources, and require applicable sources to follow MACT standards (Maximum Achievable Control Technologies). MPCA is a delegated authority for the implementation and enforcement of the major source NESHAPs.
- “Once in always in” in an EPA policy, issued in May 1995, which states that once a source is subject to a major source standard, it will always be subject to that standard, regardless of the source's subsequent toxic air emissions. Amendments to this policy were proposed in January 2007 that would allow a major source to become an area source at any time by limiting its potential to emit hazardous air pollutants (HAP) to below the major source thresholds. However, the amendment has stalled. Currently, the “Once In Always In” policy is still in place.
- PTE stands for Potential To Emit, which is the maximum amount of pollutants that could possibly be emitted by a facility over the course of a year. PTE calculations are used in determining whether a facility needs to obtain a permit, and if so, which type of permit.
- Volatile organic compounds (VOCs) are any organic compounds that participate in smog-forming reactions except for those designated by the EPA Administrator as having negligible photochemical reactivity. A list of exempted organic compounds is available in Minnesota Rule 7005.0100.