EPA Plans Maricopa County Rule Allowing Emission Offsets From Nonroad Engine Cuts

The U.S. Environmental Protection Agency (EPA) announced a soon-to-be-finalized air quality rule for Maricopa County, Arizona, at a roundtable convened by Administrator Lee Zeldin. Rep. Andy Biggs (R-AZ) attended and described the announcement.

Under Air Quality Rule 204, “Emissions Offsets Generated by Voluntary Nonroad Engine Emission Reductions,” industries in the county could use emission reduction credits generated by voluntary cuts in nonroad engine emissions. According to the announcement, the rule would give businesses more flexibility to build and expand production while ensuring that overall emissions do not increase.

Biggs said in March the EPA decided not to escalate the county’s ozone nonattainment designation under the Clean Air Act from “moderate” to “serious.” He argued that stricter federal requirements would add costs without addressing the sources of the region’s air quality problems, and said about 80 percent of emissions attributed to Arizona come from natural or international sources.

Why it matters

Builders and industrial developers in the Phoenix area could gain more flexibility in how they offset emissions once the rule is final. The rule is not yet finalized.

Source: Rep. Andy Biggs (R-AZ), October 9, 2026. Read the original release