Maximum Achievable Control Technologies (MACTs)

The Clean Air Act (CAA) requires the US Environmental Protection Agency (EPA) to establish National Emission Standards for Hazardous Air Pollutants (NESHAPs) for all categories and subcategories of major sources of 188 federally listed Hazardous Air Pollutants (HAPs) (exit DNR). A Maximum Achievable Control Technology (MACT) is one type of NESHAP based on using available technology.

The CAA also requires EPA to establish national emission standards for area sources. EPA has already issud area source MACTs for Halogenated Solvents, Perchloroethylene Dry Cleaners, Commercial Sterilizers and Chromium Electroplaters. EPA plans to develop 55 more standards affecting area sources, and these could be MACTs or GACTs (Generally Available Control Technologies).

Frequently Asked Questions
MACT

How do I find out if any MACTs apply to my company?
The best way to stay informed on MACT standards is to visit EPA's MACT schedule (exit DNR) periodically. Here you will find proposed rule dates and promulgation dates listed alphabetically by MACT category.
How do I know if I'm a major source of HAPs
A major source has the potential to emit more than 10 tons per year of any single HAP or 25 tons per year of any combination of HAPs. Note that "potential to emit" is the theoretical maximum emissions from the facility operating at full capacity 24 hours per day, 7 days per week. If you need help determining if you are a major source of HAPs, the Wisconsin Department of Commerce provides assistance to small businesses (exit DNR). You can also check with your local DNR compliance engineer or a private consultant.
When must sources comply with MACT standards?
Existing sources typically must comply within three years of the date EPA issues the MACT standard. The three years are provided so the source can explore compliance options. An existing MACT-affected source must usually submit an Initial Notification to Wisconsin DNR within 120 days of when EPA issues the MACT standard. New sources need to comply at startup.
Each MACT standard requires an affected source to submit an initial notification to the regulating agency to indicate that they are affected. USEPA Region V has delegated that authority to WI DNR so you should submit your notification to:

Dan Rosenthal
WDNR Air Program - AM/7
P.O. Box 7921
Madison, WI 53707-7921

Initial Notification form template [PDF] [exit DNR]

Do MACTs offer emission control options?
MACTs typically offer several emission control options, and each option includes extensive testing, monitoring, record keeping and reporting requirements. Emission reductions may be achieved through measures that:
  • require a process change, a substitution of material, or the reuse or recycling of material;
  • specify design, equipment, work practice, or operational methods;
  • require operator training; or
  • require collection, capture, and treatment of pollutants emitted by a process.
Affected sources may also comply by changing or limiting their operations so that the MACT would not apply to their revised operations, with some qualifications:
  • the change or limit in operation must be completed before the MACT compliance date, otherwise EPA's "once in, always in" policy [exit DNR] applies and the source is required to comply with the MACT;
  • sources that change or limit their operations must have this limit written into a federally enforceable document (typically an operation permit under chapter NR 407, Wis. Adm. Code) that is issued before the MACT compliance date. Please remember that it takes time to process a permit or other enforceable document that would establish limits to allow a source to avoid a MACT. For example, Federally Enforceable State operation permits (FESOPs) require a 30-day public review and may be subject to public hearing requests.
How are operation permits handled under MACT?
The federal operation permit program under Title V of the Clean Air Act establishes air pollution control requirements (MACT standards) that are incorporated as conditions of a facility's operation permit. If a source already has an operation permit and is subject to a MACT that was finalized after the permit was issued, the MACT requirements would be added to their operation permit as part of their five-year permit renewal.
Sources that want to take emission limits to avoid a MACT should submit a permit application to DNR or amend their application requesting the emission limits at least six months before the MACT compliance date.
Can a facility avoid a MACT with a compliance date that comes before the source's permit renewal date?
Yes. The source can ask DNR for a permit revision/renewal before the MACT compliance date. This revision/renewal would contain emission limits the source agrees to meet in order to avoid the MACT. The source should allow at least six months for DNR to process the revision/renewal.
Sources that do not have an operation permit yet and want to take limits to avoid a MACT may need to amend their permit application to indicate their desire to take limits to avoid the MACT. The permit application should indicate that the source wants their permit issued before the MACT compliance date and specify the appropriate date.
What's happening with residual risk assessments?
The Clean Air Act directs the EPA to conduct risk assessments on each source category subject to MACT standards, and to determine if additional standards are needed to reduce residual risk (PDF, exit DNR). EPA is just starting to release the results of the residual risk review for the first MACT standards and will be developing additional standards as needed to protect public health over the next few years.
Where can you get additional information?
(All links below exit DNR)

 

Air Toxics

Last Review: November 10, 2006
Next Review: November 10, 2007
Last Revised: Monday October 01 2007