"Imperial County residents suffer the health effects of profoundly dirty air, and instead of dealing with the problem, EPA responded by waiving pollution protections," said Earthjustice attorney David Baron, who brought the suit on behalf of the Sierra Club over the valley's air quality. "Without stronger anti-pollution measures the health of this community will suffer."

EPA justified its action by claiming that Imperial Valley would meet standards if it weren't for air pollution coming from Mexico. But Earthjustice contends that a detailed scientific study conducted in 1997 for EPA found that Imperial Valley would violate standards even without emissions from Mexico. The study found that violations occurred miles north of the border even on days with stagnant air. Earthjustice contends that EPA cannot grant a waiver without proof that emissions from across the border are responsible for the violations in the United States.

Scientific studies link airborne particulates to tens of thousands of premature deaths nationally, as well as to reduced lung function and aggravation of lung disease. Airborne particulates consist of soot, soil, dust, metals, and other particles emitted by industrial facilities, agriculture operations, mines, motor vehicles, and other sources.

Imperial Valley consistently violates federal health standards for airborne particulates, sometimes by wide margins. The area has the highest childhood asthma rate in the state, and its death rate from respiratory diseases is more than double that in California, according to the state's Department of Health Services.

The Clean Air Act generally required attainment of particulate standards by 1994, and reclassification – or bump up – of areas missing that deadline to a more serious air pollution category. Reclassified areas must adopt stronger pollution controls for industry, agriculture, and other sources. Imperial Valley missed the 1994 deadline. After EPA failed for six years to bump up the area, Earthjustice sued on behalf of the Sierra Club to require action. EPA responded by waiving the bump up requirement, triggering the Earthjustice lawsuit being argued today in the U.S. Court of Appeals for the Ninth Circuit in San Francisco.

Imperial County does not have an EPA-approved plan to address particulate pollution on the US side of the border, even though one was due ten years ago. "Hundreds of other communities in California enjoy clean air protections that keep their air safe," said Sierra Club Regional Director Carl Zichella, "and residents of the Imperial Valley deserve the same standard. No community in this state or this country should have to breathe air so dirty that it damages their health and the health of their children."