The Mercury and Air Toxics Standards or MATS applies to coal- and oil-fired electric utility steam generating units larger than 25 MW in capacity. It is the first national standard to reduce emissions of mercury and other toxic air pollutants (including acid gases, particulate matter, and metals). Finalized in December of 2011 for both new and existing sources, the US EPA subsequently announced reconsideration of the new source limits, ultimately arriving at less stringent limits that were finalized in March of 2013.

The rule required compliance by 2015; however, a one-year extension could granted by state permitting authorities upon request. The EPA also provided a clear pathway for reliability critical units to obtain up to an additional year to achieve compliance.

In June of 2015, the Supreme Court ruled that the US EPA should have considered cost of compliance when developing the standard and remanded the case back to the DC Circuit. The rule remained in effect while the EPA was tasked with justifying the limits imposed when the economics of compliance were considered.

AECOM Process Technologies offers several products and services that can help ensure reliable MATS compliance while also reducing the cost of compliance.