Federal lawmakers are pushing for changes to a stringent new air pollution standard imposed during the Obama administration, and the outcome of the debate will have major consequences for states and local communities in the West.

A hearing this week of the U.S. House Energy and Commerce Committee, lawmakers and state environmental regulators discussed problems with a new ozone benchmark imposed by the Obama administration in late 2015. The decision to tighten the standard from 75 parts per billion (ppb) to 70 ppb drew bipartisan opposition from a broad coalition of stakeholders, including the U.S. Conference of Mayors and National Association of Counties.

Local officials argued for keeping the 75 ppb standard, set less than a decade ago, in place. Tightening the standard any further would “negatively affect job creation and critical economic development projects,” including upgrades to transportation infrastructure, the mayors and county officials warned in comments to the U.S. Environmental Protection Agency. Since then, critics of the standard have continued to sound the alarm, including Colorado’s Democratic Gov. John Hickenlooper, who said “it would be a great idea if they suspended the standard.”

The bipartisan Ozone Standards Implementation Act (H.R. 806) would give state and local officials more time – until 2025 – to meet the 70 ppb standard. Among other provisions, the bill would also amend the Clean Air Act to require federal standards for ozone and other air pollutants to be updated every 10 years, instead of every five years under current law. “These reforms seek to improve the states’ ability to meet the new ozone and other air-quality standards without undermining efforts to ensure and promote the productive capacity of their citizens,” U.S. Rep. John Shimkus (R-Ill.), chairman of the House energy panel’s environment subcommittee, said at this week’s hearing.

The deadlines and requirements for federal air-quality standards were set decades ago, when air pollution was worse and cost-effective emission reductions were much easier to identify, Shimkus said. Today, they can be “counterproductive” and cause “unnecessary costs, duplicative efforts, regulatory delay, and economic uncertainty,” Shimkus said.

In the West, imported air pollution and other sources of “background” ozone make compliance with the 2015 standard practically impossible, according to Seyed Sadredin, executive director of the San Joaquin Valley Air Pollution Control District, which regulates air quality across eight counties in California’s Central Valley. “We could shut down all of our Valley businesses and we will not get enough reductions to meet the standard,” Sadredin testified during the hearing.

The region faces “devastating federal sanctions” even though it has dramatically cut emissions since the Clean Air Act was passed more than 40 years ago, Sadredin said. “We do not believe this is what the Congress envisioned in the Clean Air Act,” he said. “Eighty-five percent of our pollution we have no control, no regulatory authority over.”

Ground-level ozone, sometimes called smog, is tough to regulate because almost every sector of the economy produces ozone-forming emissions. Power plants, cars, trucks and factories produce these emissions but there are background sources of ozone, too. Some of those sources are natural, like wildfires. But an increasing problem in western states is air pollution that blows into the region from other countries, like Mexico and China, according to the Western States Air Resources Council.

During the 2015 debate over the ozone standard, officials and experts in the West worried that background ozone levels would push them into long-term violation of federal law, which carries serious consequences. Violation of the federal ozone standard forces state and local officials to crack down on sources of ozone-forming emissions, even if those sources are already tightly regulated. The EPA also has the final say over these new state and local requirements.

This means “EPA gets to regulate an enormous amount of economic activity,” Ray Gifford, former chairman of the Colorado Public Utilities Commission, warned during the 2015 ozone debate. “In effect, EPA becomes the planning commission, the zoning commission and the state permitting agency all rolled into one,” he said. The Associated General Contractors of America has warned that long-term violation of the ozone standard means “essentially a ban on the construction of new industrial or manufacturing facilities in this area, and it becomes very difficult even to expand existing facilities.”

The Laborers International Union of North America, a major construction union, also spoke out against the Obama administration’s ozone plan. “We cannot continue to layer environmental regulation upon environmental regulation without considering the impact it will have on our economy and our workers,” the union said.

In Colorado, Hickenlooper – the Democratic governor – was joined by other elected officials in challenging the EPA’s plan to tighten the federal ozone standard close to background levels. “They are setting us up to fail,” state Sen. Cheri Jahn (D) told National Public Radio after the October 2015 decision to ratchet down the standard. Even U.S. Sen. Michael Bennet (D), an ally of environmental groups, said he was “deeply concerned.”

“Because of the pollution that’s come in from other Western states, from across the globe, from wildfires in the West, we have significant parts of our state that would be nonattainment zones from the very beginning,” Bennet said in August 2015. “That doesn’t make any sense. That’s not going to work.”

The ozone reform bill would require the EPA to find solutions to the background ozone problem. Bennet has yet to co-sponsor the bill, but other Democrats have. In the House, U.S Reps. Jim Costa (D-Calif.), Sanford Bishop (D-Ga.) and Henry Cuellar (D-Texas) are supporting H.R. 806. A similar bill in the U.S. Senate – S. 263 – is sponsored by U.S. Sen. Joe Manchin (D-W.V.). “The current EPA rule is reviewed and implemented too frequently and leaves states unsure on which standards to implement, creating unnecessary confusion,” Manchin said last month.

At this week’s hearing, a state air quality regulator from the East Coast – Marc Cone, the air quality director of the Maine Department of Environmental Protection – praised the ozone reform bill. While the Clean Air Act has a strong track record, air quality has improved to the point that some provisions of the law, written decades ago, are no longer workable, Cone said.

Today, the EPA is setting new federal standards faster than they can provide guidance about how to meet those standards, which is “like giving someone a destination without a map,” Cone said. “The system does not work and now is an excellent time to consider changes,” he said.

The Association of Air Pollution Control Agencies (AAPCA), a professional body representing environmental regulators from 20 states, also sent a witness to this week’s ozone hearing.

“A strategic approach to modernizing the Clean Air Act is necessary and appropriate,” AAPCA President Sean Alteri – who also serves as a top air quality regulator in Kentucky – told the hearing. “The reasonable amendments [to the Clean Air Act] proposed in H.R. 806 will further enable all of our states to continue to grow our economy, enhance our quality of life, and improve our air quality,” he said.