On March 21, 2011, the EPA published three rules regarding air emissions standards in the Federal Register. Two of the three rules pertain to boilers and are specifically designed to reduce emissions of air pollutants. The two rules are: Major Source Rule (also known as Boiler MACT or BMACT), designed to reduce boiler and process heater emissions at large sources of air toxics; and the Area Source Rule, created to reduce boiler emissions at small sources of air toxics.