The EPA said it plans to strengthen regulations for emissions of ozone, a smog-causing pollutant blamed for respiratory ailments affecting millions of Americans. (Paul J. Richards/Agence France-Presse via Getty Images)

The Obama administration on Wednesday announced plans to tighten restrictions on smog-causing ozone, a move that will address a major cause of respiratory illness for millions of Americans while also setting the stage for new clashes with industry and the Republican-controlled Congress.

Environmental Protection Agency Administrator Gina McCarthy cited ozone’s damaging effects on children and the elderly in moving to toughen limits on the pollutant for the first time since 2008. Ground-level ozone, a respiratory irritant that derives from fossil-fuel burning, is linked to asthmatic attacks and other ailments and is the cause of “code red” respiratory warnings common to Washington and other urban areas during the summer months.

”We deserve to know the air we breathe is safe,” McCarthy said in a statement announcing the proposal. In deciding to revise the ozone standard, the EPA was following a legal mandate for “bringing ozone pollution standards in line with the latest science” to protect Americans from a significant health threat, she said.

McCarthy said the EPA’s long-awaited proposal would lower the allowable ozone level from 75 parts per billion, set in the final years of the George W. Bush administration, to a new standard “in the range of 65-70 parts per billion.” As part of the rule-making process, the EPA would accept comment on a wider range of possible limits, from the current 75 ppb to as low as 60 ppb, according to other officials familiar with the EPA’s plans. The agency is expected to adopt a final rule next fall.

The EPA faced a Dec. 1 deadline to revise its standards for ozone, which is one of six pollutants regulated under the Clean Air Act. Cities and counties that fail to meet the standard are required to take steps to reduce emissions to improve air quality.

Leaked details of the proposal drew sharp criticism from industry groups, which argue that tighter restrictions will lead to higher costs and losses in jobs and economic productivity. American Petroleum Institute President Jack Gerard said air quality is already improving throughout much of the country, and many states are still struggling to adjust to the last change in ozone regulations six years ago.

“Tightened standards could impose unachievable emission reduction requirements on virtually every part of the nation,” Gerard said. “Even pristine areas with no industrial activity such as national parks could be out of attainment.”

Some environmental groups had pushed for a tougher standard of as low as 60 ppb, yet many cheered the EPA’s move.

“It is clear that this would be a positive step forward, even if it doesn’t go as far as we think they should go,” said Frank O’Donnell, president of Clean Air Watch, a Washington environmental group.

GOP lawmakers already have vowed to fight any effort by the administration to toughen existing ozone standards. Last week, Republicans on the Senate Environment and Public Works Committee warned the White House that they would seek to block what they said would be one of the “most devastating regulations” ever issued by the EPA.

Industry groups had waged a month-long campaign to dissuade the EPA from adopting a stricter standard. Industry-sponsored studies — some assuming much tougher ozone limits than those the EPA is said to be contemplating — estimated economic losses in the billions of dollars.

“This new ozone regulation threatens to be the most expensive ever imposed on industry in America,” said Jay Timmons, chief executive officer of the National Association of Manufacturers. He said the proposal, coming on top of other proposed EPA regulations on greenhouse gas emissions, could reverse recent economic gains by “placing massive new costs on manufacturers and closing off counties and states to new business.”

But other groups, including state health and environmental agencies, said the claims of economic harm were exaggerated. Some noted that current law allows states considerable flexibility and a long lead time — decades, in some cases — to come into compliance. Others pointed to studies showing economic losses due ozone-related respiratory illnesses and premature deaths.

“The public should have the right to know whether the air they are breathing is safe,” said S. William Becker, director of the National Association of Clean Air Agencies. “There can be a false sense of security thinking that levels at 75 ppb are safe to breathe when scientists are saying they are not.”