EPA Office Recommends Leaving Sulfur Dioxide Rules Unchanged

Published October 11, 2017

The air quality office of the U.S. Environmental Protection Agency (EPA) recommends the agency leave federal sulfur dioxide standards at current levels after finding no evidence they are inadequate to protect human health.

On August 24, the Office of Air Quality Planning and Standards Health and Environmental Impacts Division issued a draft assessment saying it has no reason to question the “the adequacy of protection” of the current rule allowing no more than 75 parts per billion of sulfur dioxide, set in 2010.

EPA is charged with reviewing air quality standards for criteria pollutants such as ozone, lead, and sulfur dioxide every five years to determine whether, based on the best current evidence, existing standards protect public health with “an adequate margin of safety.”

Consent Decree Deadline

EPA has often missed the review deadlines, including its most recent deadline to review the sulfur dioxide standard. When EPA missed its 2015 deadline to review sulfur dioxide, the Center for Biological Diversity and the Center for Environmental Health sued the agency in the U.S. District Court for the Northern District of California to force a review.

In April 2017, EPA signed a consent decree agreeing to a January 2019 deadline to determine whether the sulfur dioxide standard needed revision to protect human health.

Endorses Current Standards

William Yeatman, a senior fellow specializing in environmental policy at the Competitive Enterprise Institute, says the decision not to make the sulfur dioxide standard more stringent is sound.

“There’s no surprise here,” said Yeatman. “Under the Clean Air Act, the EPA receives advice from the Clean Air Science Advisory Committee (CASAC) on where to set National Ambient Air Quality Standards (NAAQS) ‘at a level requisite to protect public health with an adequate margin of safety,’ which current standards are. The DC Circuit has interpreted CASAC’s role such that EPA has little latitude to deviate from its advice. Here, EPA’s action comports with CASAC’s advice.”

Although Yeatman says EPA’s decision not to make the sulfur dioxide standard more stringent is correct, he objects to the way such decisions are made.

“I should note, although EPA made the right decision this time, all too often at the direction of CASAS they make deleterious decisions to unjustifiably ratchet down air quality standards,” said Yeatman. “Politicians, not technocrats, should be setting NAAQS, since it is appropriately a policy determination.

“It is inappropriate for such consequential, costly decisions to be rendered by a technocratic body with zero political accountability,” Yeatman said.

Michael McGrady ([email protected]) writes from Colorado Springs, Colorado.


U.S. Environmental Protection Agency, “Policy Assessment for the Review of the Primary National Ambient Air Quality Standard for Sulfur Oxides,” August 24, 2017: https://heartland.org/publications-resources/publications/policy-assessment-for-the-review-of-the-primary-national-ambient-air-quality-standard-for-sulfur-oxides