Definitions for "Maximum Achievable Control Technology"
An emission limitation which is not less stringent than the emission limitation achieved in practice by the best controlled similar source, and (MACT) which reflects the maximum degree of reduction in emissions that the permitting authority, taking into consideration the cost of achieving such emission reduction, and any non-air quality health and environmental impacts and energy requirements, determines is achievable by the source.
EPA standards mandated by the 1990 amendments to the federal Clean Air Act for the control of toxic emissions from various industries. Industries range from dry cleaners to petroleum refineries
Emissions limitations based on the best demonstrated control technology or practices. This is a very high level of pollution control.