From diesel exhaust to leaking pipelines and other infrastructure, oil and natural gas development releases methane, a greenhouse gas 30 times more potent than CO2, sulfur and nitrogen compounds and toxic volatile organic compounds (VOCs) like benzene. The latter two help form lung-damaging ozone. As drilling booms, Western gaspatch pollution sometimes rivals that of major urban areas. That's increased support for better state regulations and inspired some of the first federal rules governing hydraulic fracturing ("EPA aims to clean up polluted air in Western gas fields," HCN 9/5/11).
In late February, Colorado became the first state to regulate the industry's methane emissions, and also tightened and expanded VOC rules. Though two industry trade groups fought those provisions, energy companies Anadarko, Noble and EnCana joined some environmental groups in support of the proposal. Officials estimate it will reduce annual VOC emissions by 92,000 tons, and methane by tens of thousands of tons.