LOS ANGELES, Calif.–Health advocates filed suit against the U.S. Environmental Protection Agency, alleging a national ozone standards deadline for the Los Angeles region was not met, according to court papers.

The suit, filed in Los Angeles federal court on Monday, aims to force the EPA to adopt a plan to bring air quality in the Los Angeles basin into compliance with smog regulations.

As of late this afternoon, an EPA representative had not returned a call seeking comment.

Under the federal Clean Air Act, the most polluted areas of the country, including the Los Angeles region, were required to meet the national one-hour standard for ozone no later than May 2011, according to Physicians for Social Responsibility-Los Angeles, among the plaintiffs in the lawsuit.

“Until EPA fulfills its mandatory duty under the Clean Air Act, the South Coast Air Basin’s air quality will continue to endanger the health of California citizens,” the lawsuit states.

The one-hour ozone standard limits the maximum concentration of ozone that people can be exposed to over a one-hour period. Air quality monitoring data shows that Los Angeles did not attain that standard by the deadline, according to the group.

“Ozone pollution exacerbates asthma, causes lung damage and leads to premature deaths everywhere in L.A.,” said Maya Golden-Krasner, an attorney for Communities for a Better Environment, another plaintiff.

“These harms are magnified in communities such as Wilmington and southeast L.A., where pollution from freeways and industrial sources already chokes neighborhoods,” Golden-Krasner said.

Plaintiffs in the lawsuit also include Desert Citizens Against Pollution and the Natural Resources Defense Council.

If the EPA determines the region failed to meet the national ozone standard, the South Coast Air Quality Management District would have a year to submit a new plan.

“The human costs of our failure to reduce ozone pollution are felt most acutely by the thousands of families who live with asthma,” said Martha Dina Arguello, executive director of the physicians group.

“The economic cost of asthma stands at $2.6 billion, but the human costs are incalculable,” she said. “Just imagine the pain of watching your child gasp for air during an acute asthma attack. We must get serious about protecting health and keeping health care costs down, and one way to accomplish this is to have EPA enforce the one-hour ozone standard.”