WASHINGTON, D.C. — The U.S.’s Clean Air Act stood firm as a Supreme Court decision yesterday upheld the way the American government sets air quality standards.

In a unanimous decision, all nine justices rejected arguments that the Environmental Protection Agency (EPA) must consider financial cost to industry as well as health benefits in setting standards.

They rejected the argument that the EPA took too much legislative power from Congress when it put in place tougher standards regarding ozone and soot in 1997.

However, the court threw out the EPA’s policy for implementing new ozone rules, ordering the agency must come up with a more reasonable interpretation of the law.

Edward Warren, representing the industry groups who brought the case, said they retained a right to challenge the ozone and soot standards in a lower court.

“There’s a good chance that both of these standards will fall,” he said.

The industry groups involved included the U.S. Chamber of Commerce, the National Association of Manufacturers and the American Trucking Associations (ATA).

Also involved in the case were the states of Michigan, Ohio and West Virginia.

Carol Browner, the Clinton administrator who pushed through the tougher rules, says the decision was, “a clear vindication of the work we did for public health on air pollution over the last eight years.”

The American Lung Association called the ruling, “a victory for the Clean Air Act and for the health of the American people.”

On the other side of the issue, the ATA said it, “is clearly disappointed in the Supreme Court’s ruling.”

It added that the court, “did provide some guidance” to reach the goal of clarifying the EPA’s policy on interpreting the law, “in a sensible fashion.” It added it is now looking to the Court of Appeals on remand as well as the EPA to provide further guidance.

“The ruling that the EPA exceeded its authority in attempting to impose a new ozone standard,” concluded the ATA, “coupled with the lower court’s unchallenged decision that the beneficial health effects of ozone should have been considered, are significant developments toward this objective.”

The 1970 Clean Air Act was the first major environmental-protection law enacted in the U.S. This challenge was seen as the most important environmental case before the Supreme Court in many years.