CONTRA COSTA (KCBS) — Bay Area oil refineries may have to cope with new air quality rules next year forcing them to cap their greenhouse gas emissions by as much as 20 percent as air officials have asked their staff to come up with new regulations.

The rules would apply to the Bay Area’s five oil refineries.

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“We know that air quality in the Bay Area has improved because of impressive regulation over the last 20 years but we want to continue that,” John Gioia, who is a Bay Area Air Quality Management District board member and Contra Costa supervisor, said.

Diane Bailey, with the natural Resources Defense Council, told KCBS that tighter air quality rules would benefit refinery neighbors who have had to endure a lot.

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“There’s an incredible amount of air pollution from these refineries for decades now,” she said. “No matter what the crude oil is that these refineries are taking on, whether is tar sands or not, they’re not allowed to increase pollution.

But Guy Bjerke, spokesman for the Western States Petroleum Association counters the proposed rules would undercut existing operating permits.

“We will work with them where we think we can constructively work with them and we will continue to express our opposition to the baseline and cap concept,” he said.

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The air district is not likely to vote on any new emission rules until March.