EPA concluded that its existing standard for ozone exposure was inadequate to protect public health and the agency has estimated it will cost $9.6 billion a year in increased costs for polluters to comply with the new one.

When regulators relax a standard as opposed to imposing a tougher one, the Clean Air Act contains a section designed to ensure that air quality won't deteriorate in an area.

Safeguards, which regulators refer to as "anti-backsliding" requirements, call for control measures on polluters.

Industry objected in the case of the revised ozone standard when EPA concluded it could use the "anti-backsliding" requirements, even though the agency was imposing a tougher standard rather than easing one.

In raising the ozone standard, regulators had dropped a few of the requirements, but they were reimposed by the U.S. Court of Appeals for the District of Columbia Circuit, which ruled against industry.

The EPA is imposing requirements, regardless of whether they are needed to attain the new, more stringent ozone standard, industry lawyers wrote in asking the Supreme Court to take the case.

Petitioning the court were the National Petrochemical & Refiners Association, the American Chemistry Council, the American Petroleum Institute and the Utility Air Regulatory Group.

Separately, businesses in Baton Rouge, La., also asked the Supreme Court to hear their objection to EPA's position on the new ozone standard.

Lawyers for the businesses said that if Louisiana is forced to revise its pollution control plan, over 150 Baton Rouge businesses will be forced to pay $65 million to $100 million a year, threatening thousands of jobs in an economy still overwhelmed by the impact of hurricanes Katrina and Rita, local business groups told the court.