National Emission Standards for Hazardous Air Pollutants (NESHAP) are stationary source standards for hazardous air pollutants. Hazardous air pollutants (HAPs) are those pollutants that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental effects.

EPA develops national enforcement initiatives that focus on significant environmental risks and noncompliance patterns. For Fiscal Years 2014 to 2016, the Cutting Hazardous Air Pollutants National Initiatives Strategy focuses on categories of sources that emit HAPs.

Compliance Monitoring 

• Reviewing reports and records
• Interviewing facility personnel knowledgeable of the facility
• Inspecting the processes that have emissions points subject to the standard sampling wastewater discharges, if applicable
• Inspecting against design and work practice standards
• Reviewing leak detection and repair methods

Sources subject to NESHAPs are required to perform an initial performance test to demonstrate compliance. To demonstrate continuous compliance, sources are generally required to monitor control device operating parameters which are established during the initial performance test. Sources may also be required to install and operate continuous emission monitors to demonstrate compliance. Consistent with EPA’s Clean Air Act Stationary Source Compliance Monitoring Strategy, NESHAP sources that meet the Clean Air Act definition of “major source” generally receive a full compliance evaluation by the state or regional office at least once every two years.

• Issuance of waivers
• Notification requirements
• Observation of tests
• Representative performance
• Stoppages and postponement of tests

The guidance is not a regulation, nor is it intended to change any underlying regulatory requirements specified in individual NSPS, NESHAP, MACT, state or local regulations. The guidance merely documents and clarifies existing regulatory requirements and Agency guidance on stack testing. 

For additional information on NESHAPs, MACT standards and hazardous air pollutants, see the EPA’s Air Toxics Web site.