The Clean Water Act and Clean Air Act were passed in 1970. The Clean Water Act was amended to address stormwater; the Clean Air Act was amended in 1990 to address acid rain, urban air pollution, toxic air emissions, and stratospheric ozone depletion.
U.S. EPA has finally made good on the 20-year-old air amendments by issuing standards regulating the largest remaining source of acid gas, arsenic, cyanide, mercury, nickel, and selenium: facilities that burn coal to generate electricity. About 40% of power plants produce half the nation's mercury and 75% of its acid gas emissions.
Estimated compliance cost: $10 billion.
Unlike standards for stormwater, however, the Mercury and Air Toxics Standards (MATS) allow plant managers to use widely available, proven pollution controls that more than half of coal-fired power plants already use. In addition, to ensure electricity service isn't disrupted, the agency may allow permitting authorities “to make a fourth year broadly available for technology installations, and if still more time is needed, providing a well-defined pathway to address any localized reliability problems should they arise.”
Along with the final Cross-State Air Pollution Rule, the standards represent the most significant steps toward mitigating smokestack pollution since the Acid Rain Program of the 1990s.