“each major stationary source which is in existence [between 1962 and 1977], and which … emits any air pollutant which may reasonably be anticipated to cause or contribute to any impairment of visibility in any such [national park or wilderness] area, shall procure, install, and operate, as expeditiously as practicable … the best available retrofit technology … for controlling emissions from such source for the purpose of eliminating or reducing any such impairment….” CAA § 169A.*

• It exempts 142 major park-polluting power plants in the Eastern U.S. from the legal requirement to install best available retrofit technology.
• It allows an additional 1.5 million tons per year of sulfur dioxide in the air that otherwise would be eliminated if the Clean Air Act were fully enforced.
• For many national parks, it eliminates less than half of the visibility impairment needed to meet even the first step of restoring clear skies to our parks.

1. EPA’s BART rule does not mandate that each major pollution source be evaluated for the best available retrofit technology, as the law requires; Instead, EPA’s new rule allows the major sources of park pollution ­ electric power plants ­ to avoid BART if they participate in an air pollution “cap and trade” program (known as the “Clean Air Interstate Rule,” or CAIR).
2. EPA’s plan will allow many major park polluting power plants to buy emissions “credits” from other plants rather than install modern emissions controls. For instance, there are 251 power plants in the eastern U.S. that by law must be evaluated for BART equipment. Of these, 54 currently have such equipment. Under EPA’s plan, EPA estimates that an additional 55 will install BART equipment, meaning 142 power plants will continue to operate without it.
3. Exempting these 142 major power plants from BART will mean more air pollution in our parks than if the Clean Air Act were fully enforced. If these 142 power plants were required to install BART equipment, an additional 1.5 million tons of sulfur dioxide per year would be eliminated from the electric power sector in the Eastern U.S., over and above the EPA’s plan.
4. The EPA plan would focus on improving the “average” visibility of all national parks combined. This means that air quality may get better at some parks and worse or no improvement at others. Visibility improvement is not a commodity that can be traded between parks; the law requires clear air at each and every national park.
5. The BART rule contains a host of other loopholes, such as exemptions for “de minimis” emissions, even if they contribute to hazy skies in parks, and volatile organic compounds (VOCs), whose visibility impairing properties are well documented.

  In 1999, EPA promulgated the Regional Haze Rule, which directs state, regional, and federal efforts aimed at reversing worsening visibility conditions in national parks and wilderness areas. The rule requires states to identify uniform rates of visibility improvement that will be needed to attain natural conditions by 2064. Visibility impairment is measured on the “deciview” index, a scale related to visual perception. The index has a value of near zero for a pristine atmosphere, and each deciview above zero corresponds to a small but perceptible scenic change for the worse, or increasingly hazy skies.

  The Regional Haze Rule calls for visibility improvements on the most impaired days (the 20th percentile of the days at the site with the highest deciview index) and no additional visibility impairment on the least-impaired days. The chart below shows the deciview improvement needed at select national parks in order to meet the first phase of visibility improvement (2018) under the Regional Haze Rule. It also shows that, by substituting CAIR’s “cap and trade” system for BART in the Eastern U.S., EPA will cause national parks to fall far short of meeting their visibility improvement goals by 2018.