The MACT Standards

As part of the 1970 Clean Air Act (CAA), the National Emission Standards for Hazardous Air Pollutants (NESHAP) were developed by the EPA to reduce hazardous air pollutants. The 1990 Clean Air Act Amendments (CAAA) changed the NESHAP standards to base them on technology-driven criteria. These new standards were established according to Maximum Achievable Control Technology (MACT) standards. The goal of the MACT standards is to ensure that devices are using the most effective technology available for reducing the level of hazardous air pollutants being released by combustion devices.

The requirement of the MACT standards applies to a variety of combustion devices used to burn hazardous wastes, including the following units:

• Cement kilns
• Lightweight aggregate kilns
• Hydrochloric acid production furnaces
• Certain solid waste incinerators
• Certain boilers

In 2012, the EPA adjusted the regulations for incinerators and boilers. A link to a summary of these changes can be found in the Additional Resources section.

Combustion devices that meet the requirements of the MACT standards are not regulated under the tiered system established by RCRA. Rather, owners of this type of combustion equipment must adhere to the MACT standards under the Clean Air Act. The combustion units must meet strict limits for emissions of dioxins, furans, metals, total chlorine, and other pollutants. Among other things, the units must be monitored for temperature pressure, waste feed, and levels of pollutants in the emissions. Facilities with combustion units that meet the MACT standards have a choice of pollution control technologies.

To learn more about RCRA visit our RCRA Hazardous Waste Safety Online Training web page.