Bill · H.R. 9618· House(119-HR-9618)
DEF Act
- Introduced
- 7/9/2026
- Last activity
- 7/14/2026 — Forwarded by Subcommittee to Full Committee by Voice Vote.
- Sponsored by
- Julie Fedorchak
- Cosponsors
- - 6 - 1
- Introduced
- In Committee
What this bill would do
The Diesel Engine Flexibility Act aims to amend the Clean Air Act to ensure regulatory stability for motor vehicles and engines. For a 10-year period, it establishes a "safe harbor" for specific implementation strategies described in certain guidance documents. The bill restricts the Administrator from creating new emission standards more stringent than the 2007, 2010, or Tier 4 standards during this time. If new standards are created after this period, they must include a specific lead time and application duration. Additionally, the Administrator is required to consider various economic and operational factors when developing future standards.
Yes· 3 of 4
Would business owners be better off under this?+6
The bill benefits owners of diesel vehicles by providing regulatory certainty and reducing compliance costs.
Does this make it easier to run a small business?+5
The bill provides regulatory stability and cost mitigation for owners and operators of diesel engines.
Would farmers be better off under this?+4
Farmers utilizing nonroad diesel engines benefit from increased regulatory stability and cost predictability.
The opposite· 3 of 4
Does this cut the pollution that drives climate change?-5
The bill limits the ability to implement more stringent emissions standards for a 10-year period.
Does this better protect air, water and wildlife?-5
The bill creates a moratorium on stricter emissions standards which may delay environmental protection goals.
Would people in cities be better off under this?-3
Stricter emissions limits are delayed, which may negatively impact air quality in urban areas.
Who it would affect, and how
Potential Positive Impacts for People
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Protection against operational disruptions: The bill requires the Administrator to consider the need to reduce unnecessary operational disruptions, shutdowns, and operating restrictions for owners and operators (Section 2, Section 2(2)(C)(i); Section 3, Section 3(2)(C)(i)).
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Preservation of equipment durability: The bill mandates consideration of preserving operating conditions and engine configurations that protect the durability of vehicles, engines, and their aftertreatment components (Section 2, Section 2(2)(C)(ii); Section 3, Section 3(2)(C)(ii)).
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Economic considerations for owners: The Administrator must consider the effects of new standards on resale value, financing expectations, dealer inventories, and equipment availability (Section 2, Section 2(2)(C)(iii); Section 3, Section 3(2)(C)(iii)).
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Cost mitigation: The bill requires the Administrator to consider the costs imposed on owners and operators, including downtime, repair, service, logistics, and equipment replacement costs (Section 2, Section 2(2)(C)(iv); Section 3, Section 3(2)(C)(iv)).
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Regulatory predictability through lead times: After the initial 10-year period, any new or revised standards must take effect no earlier than 5 years after they are promulgated and must apply for at least 3 model years (Section 2, Section 2(2)(B); Section 3, Section 3(2)(B)).
Potential Negative Impacts for People
- Restriction on more stringent emissions standards: For a period of 10 years, the Administrator is prohibited from implementing any regulations or standards for motor vehicles and engines that are more stringent than the 2007, 2010, or Tier 4 standards (Section 2, Section 2(2)(A); Section 3, Section 3(2)(A)).
Groups and Interests Ranking
Every group the model scored this bill for, from -10 to +10. Hover a score for the reason it gave.
- Demographic And Interest Groups
- Good For Business Owners+6Good For Farmers+4Good For Rural Residents+3Good For Urban Residents-3
- Environment Energy And Infrastructure
- Improves Environmental Protections-5Reduces Carbon Emissions-5
- Economy And Finance
- Improves Small Business Support+5
- Governance And Ideology
- Increases Federal Power-3
- 7/14/2026
- Subcommittee Consideration and Mark-up Session Held
- Forwarded by Subcommittee to Full Committee by Voice Vote.
- 3 Cosponsors added.
- 7/9/2026
- Referred to the Subcommittee on Environment.
- Referred to the House Committee on Energy and Commerce.
- 4 Cosponsors added.
- Introduced in House
Mike BostRepublican · Illinois
Jack BergmanRepublican · Michigan
Donald DavisDemocrat · North Carolina
Michelle FischbachRepublican · Minnesota
Brad FinstadRepublican · Minnesota
H. GriffithRepublican · Virginia
Michael RulliRepublican · Ohio