National Emission Standards for Hazardous Air Pollutants
Maximum Achievable Control Technology
Major and Area Sources

What is a "major source" of hazardous air pollutants?

A "major" source is defined as a stationary source that emits 10 tons or more per year of any of the 188 listed hazardous air pollutants , or 25 tons or more per year of a combination of these pollutants. These sources may release hazardous air pollutants from process operations, combustion of fuel, equipment leaks, when materials are transferred from one location to another, or during discharge through emission stacks or vents. Applicability is further defined in the individual NESHAP andMACTs.

What is an "area source"?

Area sources are defined as those sources that emit less than 10 tons annually of a single hazardous air pollutant or less than 25 tons or more annually of a combination of the 188 identified hazardous air pollutants. These sources may release hazardous air pollutants from, painting or surface coating, combustion of fuel, equipment leaks, when materials are transferred from one location to another, or during discharge through emission stacks or vents. Applicability is further defined in the individual NESHAP and MACTs.

Where can I get a full list of NESHAPS that may be applicable to me?

For a complete list of National Emissions Standards for Hazardous Air Pollutants and applicable area source standards, visit EPA's website for Major Sources and for Area Sources.

What if I am not sure that a MACT applies to me?

Contact your Air Licensing Engineer at (207) 287-7688 or DEP-Air-Licensing-Help@maine.gov. We can help determine if a major or area source NESHAP applies to you.