Why are MACT Standards Only for Certain Industries?

Posted by Earl Parker on Sep 26, 2017 4:00:00 PM

Let's Get Real About MACT

Ask any environmental compliance engineer what their biggest worry is and they will likely mention something involving MACT (maximum achievable control technology) standards. As MACT standards come to cover more and more industries, many facilities have found achieving compliance to be a significant challenge. Frequently they find that under investment in air pollution control over a number of years substantially complicates their compliance. Some have held out for political change that they assumed would lead to a revocation of these standards. Although the MACT program is firmly established by law and not subject to any executive directives or revision like some other standards, they've built programs of minimal compliance assuming that MACT would be reversed. It hasn't. It's exceedingly unlikely that it will. 

What Are MACT Standards? 

The Clean Air Act of 1970 and later the amendments made in 1990 require the EPA to regulate the emissions of hazardous air pollutants (HAPs) from industrial facilities. The six primary pollutants covered by the original CAA included Carbon Monoxide, Ground-level Ozone, Lead, Nitrogen Oxides, Particulate Matter, and Sulfur Dioxide. In time, other HAPs also came to be regulated by the EPA. EPA-Method-9-Observation-Testing.jpg

Since 1990, the EPA has set standards for specific industries based on the highest level of control possible in that industry. To develop each MACT standard, the EPA reviews the best performing major sources in a particular industry and then sets the minimum requirements or “MACT Floor” as the average obtained by the top 12% of the industry group’s major sources currently in operation. In this way, the EPA bases its MACT rules on already proven technology.  This means industry is held to a realistically achievable standard. 

All source categories and subcategories that include major sources and area sources of hazardous air pollutants are listed within Section 112(c) of the Clean Air Act (CAA). 

What Do MACT Standards Include? 

These regulations incorporate various process control methods, emissions control devices, monitoring systems, and general work practices. For example, the Boiler MACT standards may include detailed guidelines for operating boilers (such as fuel types, feed rates, boiler design, etc.) that help reduce emissions at their source. Other times, they mandate the use of certain emissions control devices, such as dust collectors or specific filter media such as PTFE membrane filters. They may also call for rigorous monitoring and preventive maintenance programs. For example, one of the early MACT standards, which was written for secondary lead smelters, requires triboelectric bag leak detection systems on all dust collectors. (In fact Auburn assisted in the creation of the EPA's Fabric Filter Guidance Document that led the EPA to identify triboelectric bag leak detection as a required alternative to opacity monitoring when it published the secondary lead MACT in 1997.)


On the one hand MACT can feel like a complex and daunting compliance challenge - particularly for companies that have viewed industrial dust collection and emissions monitoring as a check-the-box obligatory compliance task. However, with a modest investment most facilities can reach compliance within a short period of time. Often, cost effective approaches can boost performance of existing systems through upgrades and process revision. Not only can these help achieve lower emissions levels but they also can provide substantial operational benefit. Often reductions in unscheduled downtime and managed maintenance costs will pay for significant monitoring upgrades in short order. 

Auburn Systems has been helping plants meet compliance with various EPA regulations, including MACT standards for decades. Contact us today for assistance in meeting your plants environmental requirements today! 

In the meantime, just like changing the oil in your car, simple and consistent bag house maintenance will improve dust collection and industrial emissions control performance. Our industry guide outlines common sense measures. Get your copy here.

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Topics: Bag Leak Detection, MACT Reporting