Commuting will get a "whole lot worse" in the Washington region if the Obama administration moves forward with strict new regulations for smog-causing ozone in the fall, the U.S. Chamber of Commerce says.

New Environmental Protection Agency rules would jeopardize scores of infrastructure projects necessary to improve commuter congestion in growing cities such as Washington by withholding federal highway dollars until a state or region complies with the standards, the nation's largest business lobby said in a report issued Wednesday.

The Chamber's Institute for 21st Century Energy, which issued the study, showed that 13 projects are at risk in the area, jeopardizing $511 million in project development just in fiscal 2019 and 2020 if federal grants are withheld under the regulations. It plans to release other studies highlighting other major cities in the coming months.

Under the ozone rules, the EPA can restrict federal funding for roads and other transportation projects if a state or region cannot comply within a certain timeframe. EPA's regulation of ozone is part of a long-standing EPA program to counter smog and other pollutants under the Clean Air Act. The latest proposal is an update to the program that critics view as too strict and far beyond the means of any state or city to meet.

The new regulations would control ozone emissions, or smog, by ratcheting down the current regulations from 75 parts per million of ozone, to as low as 65 parts per million, which the energy institute and many other industry groups say would automatically place most of the U.S. — including Washington —in non-compliance, or "nonattainment," with the rules.

According to the EPA website, if a state or locality is placed in nonattainment, and the "deficiency is not remedied within two years of EPA's finding or disapproval, restrictions apply to the state's use of federal highway funds for projects in the nonattainment area."

Karen Harbert with the Chamber's Institute for 21st Century Energy says the Washington-area projects are "being threatened by unreasonable standards that the region will have extreme difficulty meeting."

Washington commuters "are facing some of the worst commutes in the nation, and now key projects intended to help" could be delayed indefinitely, she said. The report shows several proposed transportation projects facing a funding threat, including: new I-66 highway development in Virginia; the Purple Line light rail in Maryland; and the D.C. streetcar.

Harbert said that means the daily commute around Washington "could get a whole lot worse."

The report focuses on the hurdles facing Washington under the new regulations. But Washington is only the beginning, according to Harbert. She says the report is part of series of studies the energy institute will be issuing through August and into the fall, detailing the billions of dollars in highway and transportation projects that will be placed at risk by the ozone rules. The ozone rules are due to be made final in October.

"Ironically, withholding funding for road and public transit projects will actually result in increased ozone emissions by failing to reduce congestion and emissions from idling traffic," Harbert said.

She says the new ozone standards would place national parks such as Yosemite and others with pristine air conditions into nonattainment. Based on the strict standard, "high growth areas" such as Washington "will be most impacted," she said.

Harbert says several metropolitan areas in the country are already unable to comply, or have recently complied, with the current ozone regulations.

The Chamber and others are urging the EPA to allow states to continue to reach compliance under the current ozone rules established in 2008, before moving to new regulations that studies say would be the most expensive of any federal program.