What is an Area Source of Hazardous Air Pollutants? Why is it regulated?

Hazardous air pollutants (HAPs) are known or suspected to cause adverse environmental effects and/or serious health effects. The U.S. Environmental Protection Agency (EPA) has identified 187 air pollutants, for example, benzene, which is found in gasoline. EPA places standards, or requirements on categories of stationary sources that emit (or have the potential to emit) one or more hazardous air pollutants called national emission standards for hazardous air pollutants (NESHAP) standards. EPA lists these standards and which agency enforces the standards in tables published in the Federal Register.

Major source of hazardous air pollutants: The term "major source"  refers to any stationary source or group of stationary sources that emits or has the potential  to emit 10 tons per year of any of the 187 named pollutants, or 25 tons per year of a mixture of pollutants.

Area source of hazardous air pollutants: The term "area source" refers to facilities that release smaller quantities of toxic air pollutants. Although emission from one area source may be relatively small, multiple area sources concern environmental specialists, especially when they are in densely populated areas.

To reduce the hazardous area pollutants released by area sources, EPA places standards, or requirements, on area sources to minimize emissions. These requirements call for specific management practices and generally available control technologies (GACT). These technologies consist of methods, practices, and techniques applicable to area sources. When EPA developed these technologies, staff members considered the economic impact as well as the technical abilities of employees to operate and maintain systems for emission control.

What are Missouri's Area Source Requirements?

The following table gives area source requirements for which the Missouri Department of Natural Resources is conducting compliance-enforcement activities. Direct questions regarding standards, compliance, and reports about area sources to the agency listed as “Regulating Agency” in the table, below. The department's Air Pollution Control Program recommends that facilities submit notifications and other required reports about area sources to the air program and EPA Region 7 contacts. If you have questions regarding any of the area source regulations or need help navigating the requirements, contact the Air Pollution Control Program.

Dry Cleaners

Online Compliance Resources for Missouri Area Source Requirements

Regulating Agency Description Sort descending 40 CFR 63 Subpart Title V Permit Keywords Rule and Implementation Information Regulation Helpful Link
MoDNR Publicly Owned Treatment Works Regulations (Major and area sources) (3V) - VVV Exempt sewer company Link Link
EPA Reciprocating Internal Combustion Engines (Area sources) (4Z) - ZZZZ Exempt Internal Combustion Engines Link Link Link
MoDNR Reciprocating Internal Combustion Engines (Major sources) (4Z) - ZZZZ Exempt Internal Combustion Engines Link Link Link
MoDNR Secondary Aluminum Production (Major and area sources) (3R) - RRR Exempt aluminum Link Link
EPA Secondary Copper Smelting (6F) - FFFFFF Major Permit Copper Link
MoDNR Secondary Lead Smelting (Major and area sources) (1X) - X Major Permit lead Link Link
EPA Secondary Nonferrous Metals Processing (6T) - TTTTTT Exempt Nonferrous metals Link Link
EPA Wood Preserving Industry (6Q) - QQQQQQ Exempt Wood Preserving Link Link
EPA Wool Fiberglass Manufacturing at Area Sources (2N) - NN Major Permit Fiberglass, Wool Link Link