MACT Regulations Summary: Breaking Down NESHAP & MACT Regulations

Updated March 2025

The National Emissions Standards for Hazardous Air Pollutants (NESHAP) set specific requirements for a wide range of industries, including Maximum Achievable Control Technology (MACT) standards for emissions. Maintaining compliance requires following the standards for your individual industry, along with keeping up with reporting. Here’s what you should know about NESHAPs and MACTs and how the right software can help.

What are MACTs?

The United States Clean Air Act legally mandated that the EPA regulate the emission of hazardous air pollutants (HAPs) by industrial sources. To accomplish this mandate, the EPA developed MACT standards. MACT standards use the HAP emissions of the best-performing (thus, “Maximum Achievable”) industry sources to set the “MACT floor,” the new minimum standard that an industry must at least meet in order to comply.

“Control Technology” is not just limited to technology but also encompasses the processes, methods, systems, and techniques that are used in facilities to reduce their HAP emissions.  Under MACT standards, the technology and work practices in facilities that produce the lowest HAP emissions are used to set the standards for the rest of the industry.

For example, data from an industrial boiler’s most efficient model or setup will be used to determine the boiler MACT regulations for all other new and existing industrial boilers. In this way, the EPA ensures that the businesses that put time, money, and effort into their control technologies are not at a disadvantage when compared to those that do not. In addition, by basing the Boiler MACT rules on already proven technology, the MACT standards that industry is held to are realistically achievable.

What are NESHAPs?

Since every industry uses different technology and produces different HAPs, there are additional industry-specific standards known as National Emission Standards for Hazardous Air Pollutants or NESHAPs. These specific NESHAPs apply to all major air emission sources in every industry, though every industry has a different standard. A major air emission source of HAPs in the forestry sector will have a different NESHAP standard than a major source used during the car manufacturing process.

The NESHAPs are based on the MACT approach of setting regulations to reduce these HAP air emissions and protect public health while still being achievable and encouraging industrial development.

Determining Your Facility’s Reporting Requirements

Your facility’s status as a major or area source is determined by its potential to emit hazardous air pollutants. Potential to emit (PTE) expresses the highest possible amount of HAPs your facility could release into the environment, even if it has never actually emitted that amount.

A major source of HAPs is defined as any stationary source (or group of stationary sources) that emits at least 10 tons of any single HAP or 25 tons of multiple HAPs as defined by the EPA’s list of hazardous air pollutants.

Determining your facility’s PTE can be done using several different methods:

• Using test data from on-site emission measurements
• Material/Mass-balance calculations that compare quantities of inputs and outputs
• Source-specific models
• Emission factors that use average equipment HAP emission rates

Once you have determined if your facility is a major source of emissions, the next step is to classify your facility as new, existing, or reconstructed.

The HAP emission limits applied to your facility depend on which category it falls under, so be sure to comply with the appropriate emissions limits.

MACT Reporting Requirements

In order to demonstrate your facility’s compliance, you need to submit reports to the EPA on a regular basis outlining your activities.

Under MACT regulations, you are required to submit the following reports and notifications:

• Initial notification
• Notification of intent to conduct a performance test
• Notification of compliance status
• Performance test report
• Start-up, shutdown, and malfunction reports
• Semi-annual compliance reports

1. Initial notification

You must provide notification that states your facility is subject to the specific MACT standards within 120 days after initial start-up.

2. Notification of intent to conduct a performance test

If your facility is required to conduct an initial performance test in order to establish operating limits, you must submit a notification of intent to conduct a performance test 60 days before the test.

3. Notification of compliance status

You must submit a notification of compliance status (NCOS) to the EPA 30 days after the initial compliance period. The compliance period begins on facility start-up and ends on the last day of the first full month afterward.

In this notification, you must do the following:

• Certify whether your major source facility is in compliance with all MACT regulations.
• Include data and calculations that demonstrate your compliance with all of your coating operations, control devices, and the transfer efficiency of any equipment.
• Describe any deviations from compliance, including the cause and calculations used to determine the noncompliance situation.
• A summary of the results of initial performance testing
• A list of your established operating limits and a summary of the calculations used to determine them.
• A statement declaring if you have implemented the work practice standards outlined by the regulations.
• Identify the compliance option used for coating operations.
• Include company contact information.
• Include the date of the report, with the beginning and end date for the reporting period.
• Contain a signed declaration from a responsible official that the report is truthful, accurate, and complete.

4. Performance test report

If you use add-on control devices and have established operating limits for your facility, you must submit a report on the full results of the performance testing and transfer efficiency within 60 days of the testing.

5. Start-up, shutdown, and malfunction reports

A start-up, shutdown, and malfunction report must be submitted within 2 days of the event, and a follow-up letter within 7 days of the event if the event that occurred is not consistent with your start-up, shutdown, and malfunction plan.

If the actions taken were consistent, the report must then be submitted semi-annually.

6. Semi-annual compliance reports

Semi-annual compliance reports must be submitted by July 31 and January 31 each year.

The semi-annual compliance reports must:

• Include company contact information
• Include the date of the report and the beginning and end date for the reporting period.
• Contain a signed declaration from a responsible official that the report is truthful, accurate, and complete.
• Identify the compliance option used for coating operations.
• If you fell out of compliance at any time, describe any deviations during the reporting period, including (but not limited to) a description of the event, the deviation period, the reason for the deviation, any and all calculations used to determine HAP emissions during the event and support the claim of deviation.
• If you were fully in compliance, demonstrate your compliance by providing the calculations for all of your coating operations. Your HAP air emissions must be within the EPA limits.

Achieving Compliance With Your Industry’s NESHAP

In order to comply with the NESHAP for each industry, an entity can demonstrate compliance in three ways:

1. Averaging emissions with MACT model point value equations.
2. Using HAPs-compliant materials.
3. Introducing control equipment.

A combination of these three options can be used to stay compliant, but this must be considered part of emissions limits based on a 12-month rolling average. This is true in all cases except when an add-on control device is used. In this case, compliance is determined through emissions testing.

If your facility uses an add-on emission capture system and control system to reduce your emissions, you may be required to set operating limits. You are not required to meet any operating limits for any coating operations without add-on controls.

Unlike emission limits, operating limits are determined individually for each facility based on its equipment. These operating limits are determined during the initial performance testing of your capture and control systems.

If you have previously done performance testing on a specific control device/capture system, you may use this earlier data to determine operating limits for that device rather than perform another test with approval from the EPA.

Once you have established all of your facility’s relevant operating limits, you are responsible for continuously monitoring your operations and ensuring your compliance.

When you are reporting to demonstrate compliance, you are required to provide any results from performance testing, records of maintenance for your capture or control systems, and documentation supporting your operating limit compliance.

You are also required to notify the EPA 60 days in advance of your initial performance test and provide the result no later than 60 days afterward.

MACT Model Point Value

These industry-specific NESHAPs outline how each industry must comply with EPA regulations, which can be a complex and difficult process. For example, calculating your average emissions with MACT model point value equations (one method of demonstrating compliance) is no small task. A facility can otherwise show compliance by:

• Using only HAPs compliant materials and being able to prove this change through reports
• Installing and utilizing control equipment, like filters, in the facility. 

Though there is an initial investment in complying with these air emissions regulations, becoming more efficient has actually seen some facilities reduce their overall operating costs over a short period of time.

The MACT model point value is a figure that is used as a substitute for emission levels for each MACT standard. They only apply to MACT standards and cannot be used in the calculation of any other emission factors. The value is used as a way of ranking the performance of different techniques that reduce HAP emissions. Using this option to show MACT compliance allows you to take different approaches in choosing your reduction techniques.

Each MACT standard (or NESHAP) provides you with the equations to calculate the MACT model point value. It is based on the HAP content of the material and the application method that you’re using. The values for each approach are then averaged and compared to the limits that are given in the MACT standard documentation. This allows you to see if your operations are in compliance.

The equations used in calculating the MACT model point values only account for the HAP content and the application method used to apply the material. These two factors are seen as easy to determine. Other factors that play a role in emissions (such as part thickness, operator technique, curing time, etc.) are much harder to evaluate and are not accounted for in the equations.

Calculating the averaging emissions using the point value equations can become an overly complex process, especially if several different application methods are used at your site. The use of EMS software to ensure accuracy is highly recommended but not essential.

Taking the Best Approach to Compliance

Probably handling your facility’s NESHAP and MACT requirements is key to maintaining compliance. You can rely on ERA’s NESHAP and MACT Reporting Software to streamline the entire process. Our platform handles a full range of HAPs, VOCs, VHAPs, GHGs, NOx, Sox, particulate matter, and other pollutants. Automated calculations and rigorous QA/QC deliver the highest level of accuracy.

Save time and money by automatically generating air emission reports on a pre-set schedule or on demand (such as in response to accidental releases). Reports come in a digital format that can be uploaded to state environmental reporting platforms where applicable. ERA’s software incorporates industry-specific reports across a wide range of NESHAPs.

Looking to put your best foot forward when it comes to NESHAP and MACT compliance? Let’s talk about how ERA can meet your facility’s unique needs. Book a discovery call with one of our project analysts today.