National Emission Standards for Hazardous Air Pollutants (NESHAPs)

Understanding the NESHAP Regulations & Categories

The National Emission Standards for Hazardous Air Pollutants (NESHAP) are regulations created to control Hazardous Air Pollutants (HAP) emissions of stationary sources. These standards apply to a wide range of source categories, including boilers, waste incinerations, and manufacturing sites, to reduce environmental risks and regulate compliance. The regulations are promulgated under the 1990 Clean Air Act (CAA) codified at 40 CFR Part 63 (where regulations prior to 1990 CAA are in 40 CFR Part 61).

Who is Subjected to NESHAP Regulations?

Determining the applicability of NESHAP regulations can be complex. The general applicability guideline depends on the facility’s industrial process details, emissions levels, technical and regulatory resources, and source category designations.

The EPA has identified three main types of sources subject to NESHAP standards:

1. 1. Major sources – Facilities that meet any of the following criteria:
      1. Emit more than 10 tons/year of a single HAP, or
      2. Emit more than 25 tons/year of any combination of HAP, or
      3. Are subject to stricter standards based on Maximum Control Technology (MACT)
   2. Area sources – Facilities that:
      1. Emit smaller quantities than a major source but are included in regulated source categories
      2. Are subject to less stringent standards for small emitters based on Generally Available Control Technology (GACT)
   3. Demolition/renovation projects with asbestos containing materials

Key Components of NESHAP

NESHAP regulations include several core components that define compliance obligations and rules:

1. 1. Applicability Criteria – Provisions that identify which stationary source categories are subjected to a rule. For the full list of provision rules and NESHAP source categories with codified federal regulations, head over to the EPA website here.
   2. Emission Limits – Emission standards that limit air pollution which are generally expressed in the unit of mass of pollutant emitted per unit volume of effluent gas (PPM, ug/m3).
   3. Testing & Monitoring Requirements – Initial performance testing (often via stack testing) is usually required to demonstrate compliance with emission standards. In addition to initial testing, facilities must conduct ongoing monitoring of key control equipment to ensure continued performance. This includes:
      1. Baghouse: Monitoring and recording pressure drop across filters to evaluate performance and detect leaks
      2. Scrubber: Monitoring pH level and liquid flow rate to verify pollutant removal efficiency
      3. Etc.
         Facilities may also be required to install Continuous Emissions Monitoring Systems (CEMS) to measure pollutant concentration and gas flow rates. This requirement is typically for larger sources and units with significant potential to emit (PTE).
         Note: Fence Line Monitoring: In some cases, facilities may be required to perform ambient “fence line” monitoring to track pollutant concentrations at property boundary. This helps verify that emissions controls effectively protect surrounding communities.
   4. Reporting Requirements – NESHAP rules include multiple reporting stages to demonstrate and maintain compliance:
      1. Initial Notification: Submitted shortly after the facility becomes subject to a NESHAP rule. This report identifies the affected source and its compliance schedule.
      2. “Notification of Compliance Status” (NOCS): Submitted after initial performance testing or compliance demonstration. The NOCS certifies that the facility has met all applicable standards and monitoring requirements.
      3. Ongoing Compliance Reports: Typically submitted semi-annually or annually, these reports summarizes monitoring results, deviations, and corrective actions.
   5. Recordkeeping Requirements – Robust recordkeeping is a critical element to NESHAP compliance and enforcement. Facilities must maintain comprehensive records demonstrating continuous compliance with emission limitations and operating standards. Records generally include:
      1. Results of performance tests and monitoring data
      2. Maintenance logs and calibration records for monitoring equipment
      3. Operating parameter data for control devices (e.g. scrubber flow rates, baghouse, pressure drops)
      4. Copies of all submitted notifications and compliance reports
      5. Records of deviations, corrective actions, and inspection findings

These records must be retained for minimum period (commonly 5 years) and made available for inspection by the permitting authority or EPA upon request. Consistent and accurate recordkeeping not only demonstrates compliance but also protects facilities from enforcement actions in event of audit or inspection.

Compliance Monitoring of NESHAP Regulations

Compliance with NESHAP involves initial compliance and ongoing verification. EPA often conducts inspections of facilities, which may include:

1. 1. Reviewing reports and records
   2. Interviewing facility personnel knowledgeable of facility
   3. Inspecting processes with emissions points, and if applicable, sampling wastewater discharges
   4. Inspecting against design and work practice standards
   5. Reviewing leak detection and repair methods

Facilities subjected to NESHAP regulations are required to perform an initial performance test to demonstrate compliance. Continuous compliance is demonstrated through regular monitoring of control device operating parameters that are established during the initial performance test (or through installation and operation of CEMS. Source categories that fall under “major sources” generally receive full compliance evaluations

(FCE) by the state or regional office at least once every two years, in line with the EPA’s Clean Air Stationary Source Compliance Monitoring Strategy.

Navigating NESHAP Regulation Challenges & Requirements

Maintaining compliance with NESHAP regulations requires precise planning and proactive management, particularly in areas such as stack testing. The EPA has issued guidance to address common challenges in conducting stack tests. Examples include:

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

By staying informed with regulatory and reporting updates, facilities can avoid delays and enforcement actions.