Dive Brief:

• EPA Administrator Scott Pruitt has granted two petitions against air quality permits issued by North Carolina officials for Duke Energy coal plants under the National Ambient Air Quality Standards (NAAQS), asking two state permitting agencies to further justify or alter their permits. 
• The petitions, brought by the Sierra Club, assert that the permits lack proper accounting mechanisms for sulfur dioxide (SO2) emissions under NAAQS and that they aim to attain SO2 standards approved in 1971, not a more stringent standard finalized in 2010. 
• Duke says it believes the two plants — the 2,422 MW Roxboro plant and the 376 MW Asheville plant — are operating within the updated NAAQS standard. The two North Carolina agencies that issued the permits have 90 days to respond. 

Dive Insight:

The Trump administration is busily rolling back environmental regulatory standards, but not all enforcement of Obama-era rules has stopped.

On June 30, Pruitt signed two orders granting petitions against permits issued by North Carolina environmental agencies. The orders were published in the Federal Register on Wednesday. 

In their petitions, the Sierra Club asserts that air quality permits issued by the North Carolina Department of Environmental Quality (DEQ) for Roxboro and the Western North Carolina Regional Air Quality Agency (WNCRAQA) for the Asheville plant are incomplete and misdirected. 

North Carolina regulations require permits issued by state agencies to comply with the NAAQS to have specific accounting mechanisms for emissions, which the petitions argue both permits lack. And the permits, the Sierra Club says, only aim to attain the SO2 standards approved in the original NAAQS rules in 1971, not the updated standards finalized by the Obama administration in 2010. 

The difference is significant. The 2010 update tightened SO2 standards to 75 parts per billion (ppb) over a one-hour time period. The 1971 standard stood at 140 ppb over a 24-hour time period, almost double the current allowance. 

In their response to the petitions, WNCRAQA argued that because EPA is still reviewing compliance with the 2010 NAAQS standard, it cannot issue permits to comply with those updated standards. DEQ said that it has begun monitoring SO2 at the Roxboro plant to comply with the new standards.

Those justifications aside, the EPA said the permits do not adequately explain when the 2010 standards will apply to the two coal plants and how they would be monitored. In granting the petitions, it directed the two agencies to better explain when the new standards apply in the permits and how they will be measured.

Sierra Club staff attorney Bridget Lee said the EPA could have gone further by including more specific directions for the two state agencies on how to alter their permits. But she praised the agency for affirming that permits for NAAQS should reflect the most recent standards, even as compliance reviews of multiple jurisdictions are active.   

"To EPA’s credit," she said, "they do say that argument doesn’t hold water and these things operate in parallel."

EPA did not respond to requests for comment.