Saturday, July 30, 2011

EPA Proposes New Air Standards for Oil and Gas Wells

In response to a court order arising from a complaint filed by WildEarth Guardians and the San Juan Citizens Alliance and a resulting consent decree, the Environmental Protection Agency has proposed New Source Performance Standards and revised National Emission Standards for Hazardous Air Pollutants for air emissions from oil and gas production.  For NSPS, the EPA has long had a source category for crude oil and natural gas production, but its only standards under this category have been for natural gas processing plants.  The proposed rule would, for the first time, set NSPS for volatile organic compounds from producing wells.   Since 1992, the EPA also has included oil and gas production as a major source for which a NESHAP must be set, and in 1999 the EPA set maximum achievable control technology standards for this source.  Its proposed rule revises the MACT standard for storage vessels and small dehydrators used in oil and natural gas production.  The proposed rule does not change the EPA's area source (generally available control technology) standards for oil and gas production.

Notably, the EPA's rule would require "reduced emission completion" ("green completion") and pit flaring for new hydraulically fractured and refractured wells; these techniques capture and reduce VOCs emitted.  (The EPA considers refracturing to be a modification and thus to trigger NSPS.)  Chesapeake Energy claims that reduced emission completions are not "available for every well that is drilled and completed"  because the process "requires special equipment and the installation of a natural gas gathering line and sales meter prior to well flowback and testing."

For hazardous air pollutants from oil and gas production, the EPA's rule would apply MACT 95 percent emission reduction standards to "every storage vessel at major source oil and natural gas production facilities" and would set a new standard for benzene, toluene, ethylbenzene, and xylene (BTEX) emissions from small glycol dehydrators used in oil and gas production.  These dehydrators remove water and hazardous air pollutants from natural gas.  "The proposed MACT standards for the subcategory of small dehydrators at oil and gas production facilities would require that existing affected sources meet a unitspecific BTEX limit of 1.10x10-4 grams BTEX/standard cubic meters (scm)-parts per million by volume (ppmv) and that new affected sources meet a BTEX limit of 4.66 x10-6 grams BTEX/scm-ppmv."

The EPA's news release and information page on the new standards provide more detail.

-Hannah Wiseman

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