There will likely be significant changes in how petroleum refineries and chemical plants calculate their emissions of volatile organic compounds (VOCs) following EPA’s agreement with environmental groups to amend its official emissions factors. 

In a consent decree filed with the U.S. District Court for the District of Columbia, the Agency agreed to issue final rules amending emissions factors used to estimate VOC releases from flares, tanks, and wastewater treatment systems by the end of 2014.  The Agency may also decide that revisions are not necessary, but this can be done only after a public comment period.

The agreement settles a suit brought against the Agency in May 2013 by the Environmental Integrity Project (EIP), which represented community groups in Texas and Louisiana. 

3-year review

The EPA maintains its official Compilation of Air Pollutant Emission Factors (AP-42), an essential compliance tool that lists formulas for calculating regulated emissions from many industrial sources and processes.  The Clean Air Act at 42 USC 7430 requires that the EPA review and, if necessary, revise emissions factors for carbon monoxide, VOCs, and nitrogen oxides at least every 3 years.

According to the EIP complaint, the Agency has not reviewed some of the factors for the above sources for over 20 years. “U.S. refineries reported releasing 37,895 tons of volatile compounds from flares, tanks, and wastewater treatment plants in 2010 alone,” states the EIP. “However, recent EPA studies have measured actual emissions of volatile and toxic compounds from U.S. refineries at levels 10 to 100 times higher than estimates based on emission factors.” 

The basic problem with air emissions factors is that they assume that all relevant process equipment is maintained.  However, equipment frequently does not operate as it should because of operator error, poor maintenance, or maintenance that was not performed at all.  In such cases, actual emissions may greatly exceed emissions estimated with AP-42 factors.

Proposal in August

The consent agreement stipulates that by August 19, 2014, the EPA must either propose revisions to emissions factors used for flares, tanks, and wastewater treatment systems or propose a determination that such revisions are not necessary.  Final revisions or final determinations that revisions are not needed must be issued by the Agency no later than December 19, 2014.  The deadlines may be modified by mutual consent of the parties or by the court on motion from the EPA “for good cause.”

The EIP undertook negotiations with the EPA on behalf of the Air Alliance Houston, Community In-Power and Development Association, Louisiana Bucket Brigade, and Texas Environmental Justice Advocacy Services. 

The consent decree