A dairy farmer group based in Modesto has pledged to keep following air quality rules even if they are suspended next month.
The rules deal with smog-forming emissions from manure and other dairy sources in the San Joaquin Valley. They were challenged by an environmental group that wants them toughened.
The critics won a court order directing the San Joaquin Valley Air Pollution Control District to suspend the rules pending further study of how they affect public health.
The district board on Thursday set a May 21 hearing where it could take this action. The board is scheduled to review the revised study June 18 and could decide to change the rules or restore them as is.
The farmers group, Western United Dairymen, said members have invested in measures aimed at complying with the three-year-old rules.
"This is not a responsibility that dairy families will shy away from," Turlock area farmer Ray Souza, the group's president, said in a news release. "We are proud of the role that we play, along with our fellow Californians, in making our state a better place to live."
The rules cover volatile organic compounds, which mix with other pollutants and sunlight to form smog. Following the standards would remove 28 percent of these substances at affected dairies and 5 percent of the total from all valley sources, district officials said.
The rules apply to farms that have 1,000 or more milking cows and were built before 2004, about two-thirds of the cows in the valley. Farms built since then are under another set of rules.
Dairy farmers generally supported the 2006 action because they got more than 70 options for meeting the standards. These include installing pollutant-trapping devices in cattle enclosures, covering feed and promptly tilling manure into fields.
The rules were challenged by the Association of Irritated Residents, based in Kern County. A court rejected most of its claims but did say the public health issue needed more study.
The plaintiffs' lawyer, Brent Newell, said the rules did not mandate any practices beyond what dairy farmers already were doing.The Fresno Bee contributed to this report.
Bee staff writer John Holland can be reached at email@example.com or 578-2385.