A rule proposed by the Environmental Protection Agency (EPA) directs 36 states to revise their Clean Air Act State Implementation Plans (SIPs) to eliminate exemptions for excess emissions of air pollutants at power plants during startup, shutdown, or when the plant malfunctions.

The rule proposed on Feb. 12 responds to a petition for rulemaking filed by environmental group the Sierra Club. That petition challenged how emissions during times of facility startup, shutdown, or malfunction are treated in SIP provisions that the EPA had approved in the past.

"Many of these state plans are outdated and are not consistent with modern rules or recent court decisions," the EPA said as it proposed the rule. The agency also said the rule would "improve national consistency and provide clarity for the treatment of emissions" during times of startup, shut down, and malfunction.

The EPA proposes to allow affirmative defenses in SIPs for excess emissions that occur when a facility is experiencing a malfunction (an unplanned event) but not for excess emissions that occur when a facility is operating in a planned startup or shutdown mode. The agency also proposed to give the 36 states identified to have SIPs with provisions that are inconsistent with the Clean Air Act 18 months to correct and submit their state plans to the agency. That period would begin as soon as the EPA makes an "inadequacy" finding that calls on each state to revise and resubmit its plan.

The proposal is currently open for comment until April 12. Comments, identified by Docket ID No. EPA-HQ- OAR-2012-0322, may be submitted at www.regulations.gov.

Sonal Patel is POWER’s senior writer (@Sonalcpatel, @POWERmagazine).

This article was first published in POWERnews on Feb. 28.