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 at http://www.epa.gov/ttn/atw/mactfnlalph.html and for Area Sources at http://www.epa.gov/ttn/atw/area/arearules.html.

What do I need to do if I'm considered an "area source"?

The requirements found in these regulations vary.  Below are a few NESHAP that impact area sources.

What do I need to do if I become a "major source"?

All these regulations have notification requirements, however, they tend to vary from source category to source category. If your facility becomes a major source which is subject to Neshap regulation, you should contact Maine DEP's Lisa Higgins at (207)287-7023, Lisa.Higgins@Maine.gov for further notification information. 06-096 CMR Chapter 140, "Part 70 Air Emissions License Regulations," requires all major sources to have a Title V Air Emissions License issued by the Department. Click here for more information about Title V Air Emissions licenses.

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

Contact Maine DEP's Lisa Higgins at (207)287-7023, Lisa.Higgins@Maine.gov or your Air Licensing Engineer. We can help determine if a major or area source NESHAP applies to you.