Diesel Emissions Reduction Act of 2025
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Would reauthorize the EPA's diesel emissions reduction program through fiscal year 2029 by extending an expiring funding deadline in the Energy Policy Act of 2005. The program provides grants, rebates, and loans to replace or retrofit older diesel engines with cleaner pollution-control technologies.
What this bill would do
What it would do
The bill would reauthorize the EPA's diesel emissions reduction program by extending its authorization through FY2029. It does this by making a single targeted amendment to the Energy Policy Act of 2005 — striking the year "2024" and inserting "2029" — which allows the program to continue providing grants, rebates, and loans for replacing or retrofitting diesel engines with pollution-control technologies.
The bill does not change the program's structure, funding levels, or eligibility rules. It solely extends the period during which the program is authorized to operate, allowing it to continue awarding financial assistance to entities that replace or upgrade older, higher-polluting diesel engines.
Key provisions
- 1Would reauthorize the EPA diesel emissions reduction program by extending its authorization deadline from 2024 to 2029.
Who would be affected
Fleet operators, municipalities, school districts, port authorities, and other public and private entities that own older diesel equipment and would seek EPA grants, rebates, or loans under the program. The EPA, which administers the program, would be directed to continue operating it through FY2029.
Why it matters
Without reauthorization, the diesel emissions reduction program would lapse after FY2024, cutting off federal financial assistance to entities seeking to replace or upgrade high-polluting diesel engines. Extending it through FY2029 would allow fleets, ports, school districts, and other operators to continue applying for EPA funding to reduce diesel exhaust — a source of particulate matter and nitrogen oxides linked to respiratory illness.
What would change
Changes to existing law
Reauthorizes Energy Policy Act of 2005 (Sec. 2)
Amends Section 797(a) (42 U.S.C. 16137(a)) by striking '2024' and inserting '2029', extending the diesel emissions reduction program through FY2029.
Agencies directed to act
Funding and costs
Congressional Budget Office estimate
CBO estimates the bill would cost $390 million over the 2026–2030 period and $400 million over the 2026–2035 period, with no effect on direct spending, revenues, or the deficit.
S. 2235 would authorize $100 million per year for fiscal years 2026 through 2029 for the EPA to provide grants and rebates to state, local, and tribal governments for programs that reduce diesel engine emissions. CBO estimates that implementing the bill would require discretionary appropriations (funding that must be approved annually by Congress, distinct from automatic mandatory spending) totaling $390 million over the 2026–2030 period and $400 million over the 2026–2035 period, based on historical spending patterns for similar activities. The bill would have no effect on direct (mandatory) spending or revenues, and thus no impact on the deficit. CBO identified no intergovernmental or private-sector mandates in the bill.
How implementation would work
The EPA would continue administering the existing diesel emissions reduction program under the framework already established in the Energy Policy Act of 2005. No new rulemaking or structural changes are required — the single amendment simply moves the authorization deadline forward five years, allowing the agency to continue awarding grants, rebates, and loans to eligible applicants through FY2029 under existing program rules and procedures.
Legislative status & sources
Latest action
Placed on Senate Legislative Calendar under General Orders. Calendar No. 226.
Official CRS summary
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This bill reauthorizes through FY2029 a diesel emissions reduction program under which the Environmental Protection Agency provides grants, rebates, or loans for replacing diesel engines or retrofitting the engines with pollution control technologies.
Legislative subjects
Air quality; Climate change and greenhouse gases; Environmental Protection; Motor fuels; Motor vehicles