Manufacturers Take Unlawful EPA Air Standard Fight to Supreme Court
New NAM Analysis Finds Rule Threatens Nearly $1 Trillion in Manufacturing Investment and More Than 122,000 American Jobs
Washington, D.C. – Today, the National Association of Manufacturers joined a coalition of leading business groups in filing a petition for certiorari asking the U.S. Supreme Court to review and reverse the D.C. Circuit’s decision allowing the Environmental Protection Agency’s unlawful and unworkable air quality standard for fine particulate matter, or PM2.5, to stand.
“The Biden administration took an unlawful regulatory shortcut to impose an unworkable air standard that makes it harder to grow manufacturing in America and create well-paying jobs,” said NAM Chief Legal Officer and Corporate Secretary Linda Kelly. “Manufacturers have fought this rule from the beginning because the consequences for investment, growth and American competitiveness are enormous: investment, jobs and America’s ability to compete.
“In 2025, the EPA under the Trump administration agreed, asking the court to vacate the new PM2.5 standard and echoing manufacturers’ concerns that the previous administration had exceeded its authority.
“Yet, the D.C. Circuit allowed the rule to stand, relying on a legal argument the previous administration never invoked to defend its actions. An agency cannot simply disregard the substantive safeguards required by Congress to impose a sweeping new regulatory burden—and a court should not rescue an unlawful rule with an argument the government never raised.
“Manufacturers need the ability to obtain permits, expand operations, modernize facilities and invest in communities across the country. This standard puts those investments and the jobs they support at risk.”
In 2024, the EPA lowered the National Ambient Air Quality Standards for PM2.5 from 12 micrograms per cubic meter to 9. According to new NAM analysis, a standard of 9 threatens at least 474 manufacturing projects announced in the United States since Jan. 1, 2025—representing nearly $1 trillion in investment and more than 122,000 American jobs.
Background:
The Clean Air Act requires the EPA to conduct a thorough review of the NAAQS every five years to determine whether existing standards should be retained or revised. Following a complete review in 2020, the EPA retained the PM2.5 standard of 12 micrograms per cubic meter.
The previous administration subsequently reopened that completed review and in 2024 lowered the standard to 9 micrograms per cubic meter. The NAM and seven leading business groups challenged the rule in the D.C. Circuit, arguing that the EPA lacked authority to revise the standard through an off-cycle reconsideration without conducting the thorough review required by the Clean Air Act.
In November 2025, the EPA reversed the federal government’s position in the litigation and asked the D.C. Circuit to vacate the rule, agreeing with the NAM that the previous administration had used an unlawful regulatory shortcut.
On June 26, 2026, the D.C. Circuit nevertheless upheld the rule, concluding that the EPA could revise the standards outside the five-year review cycle without completing a thorough review. In reaching that conclusion, the court relied on a provision of the Clean Air Act that the previous administration had not invoked in defending the rule.
-NAM-
The National Association of Manufacturers is the largest manufacturing association in the United States, representing small and large manufacturers in every industrial sector and in all 50 states. Manufacturing employs nearly 13 million men and women, contributes $3 trillion to the U.S. economy annually and accounts for nearly 52% of private-sector research and development. The NAM is the powerful voice of the manufacturing community and the leading advocate for a policy agenda that helps manufacturers compete in the global economy and create jobs across the United States. For more information about the NAM or to follow us on Twitter and Facebook, please visit www.nam.org.
