Oklahoma 2026 Regular Session

Oklahoma Senate Bill SB2078

Introduced
2/2/26  

Caption

Motor vehicles; creating the Oklahoma Diesel Engine Freedom Act. Emergency.

Summary

SB 2078, the “Oklahoma Diesel Engine Freedom Act,” would assert state authority to regulate emissions standards for vehicles operating solely within Oklahoma and declare that federal requirements mandating diesel exhaust fluid (DEF) use in diesel engines are null and void as applied to intrastate activity. The bill is framed as a constitutional challenge to federal regulation, relying on the Tenth Amendment and the state’s claimed power over commerce that does not cross state lines. The bill would also affirm that the manufacture, sale, and installation of diesel engines and equipment that do not require DEF are lawful in Oklahoma. It would prohibit state agencies, political subdivisions, and officers from restricting or attempting to enforce federal DEF-related mandates, and it would declare certain non-DEF engines manufactured and sold exclusively in-state exempt from federal emissions standards, provided they are labeled for in-state use and not exported for use elsewhere unless compliant with federal law. In addition to the regulatory changes, SB 2078 would create civil fines for any state agency, local government, or individual found enforcing or attempting to enforce a federal DEF mandate in Oklahoma. The bill sets penalties at up to $500 for a first offense, $1,000 for a second offense, and $2,500 for third and subsequent offenses, with a warning for first-time offenses and an administrative hearing process for appeals. It also repeals 47 O.S. 2021, Section 12-423, which relates to emission control systems, and includes an emergency clause so it would take effect immediately upon passage and approval. The available context shows no committee transcript or recorded votes, so there is no documented floor or committee debate to gauge detailed support or opposition. Based on the bill text, the overall sentiment appears strongly anti-federal-regulation and pro-industry/pro-diesel-engine autonomy, with the sponsor presenting the measure as a protection against unconstitutional federal overreach and burdensome emissions rules. The main point of contention is likely to be the bill’s attempt to nullify or refuse enforcement of federal emissions requirements, which raises federal preemption and constitutional issues. Potential opponents would include state agencies concerned about compliance, environmental regulators, and entities that favor uniform emissions standards, while supporters would likely be diesel engine manufacturers, vehicle owners, and others seeking relief from DEF-related requirements and emissions controls.

Impact

If enacted, SB 2078 would substantially alter Oklahoma motor vehicle and emissions law by repealing an existing emissions-control statute and replacing it with provisions that prohibit state and local enforcement of federal DEF-related mandates for intrastate vehicles. It would also create new state-law protections for non-DEF diesel engines, authorize their manufacture and sale within Oklahoma, and impose civil penalties on officials or others who attempt to enforce the targeted federal requirements. The bill would likely invite legal conflict over federal supremacy and the extent of state authority to exempt intrastate vehicles from federal emissions standards.

Sentiment

There is no recorded committee discussion or vote history in the provided materials, so sentiment cannot be measured from legislative debate. The bill text itself reflects a clear pro-passage posture from the sponsor, emphasizing state sovereignty, opposition to federal regulation, and relief from what the bill describes as unconstitutional and burdensome mandates. The absence of recorded opposition or support in the supplied context leaves the broader legislative sentiment indeterminate.

Contention

The central controversy is whether Oklahoma can lawfully declare federal DEF mandates null and void for vehicles operating solely within the state and bar state officials from assisting in enforcement. Critics would likely argue that emissions regulation is preempted by federal law and that the state cannot exempt intrastate vehicles from federal standards in the manner proposed. Supporters would likely argue that the bill protects state sovereignty, intrastate commerce, and diesel users from costly compliance requirements. The fine provisions for enforcement activity are also likely to be contentious because they would penalize state or local actors for carrying out federal-related enforcement.

Companion Bills

No companion bills found.

Previously Filed As

OK SB457

Motor vehicles; creating the Oklahoma Diesel Engine Freedom Act. Emergency.

OK SB749

Higher education; creating the Oklahoma Higher Education Freedom of Expression and Transparency Act. Effective date. Emergency.

OK HB1751

Motor vehicles; Service Oklahoma; various changes; licenses; identification cards; effective date; emergency.

OK SB943

Health care; creating the Oklahoma Medical Freedom Act; prohibiting certain discrimination; granting certain protections; creating certain cause of action. Emergency.

OK HB2134

Motor vehicles; Oklahoma Motor Vehicle Act of 2025; effective date.

OK SB784

Motor vehicle repair; creating the Oklahoma Motor Vehicle Consumer Protection Act; requiring certain written consent for certain service work; directing Insurance Department to adjust certain maximum daily storage rates. Emergency.

OK SB641

Motor vehicle repair; creating the Oklahoma Motor Vehicle Consumer Protection Act; establishing certain hourly market rate for labor. Effective date.

OK HB1957

Motor vehicles; requiring certain vehicles be registered as a motor vehicle; national standards; authorizing Service Oklahoma to register and license certain vehicles; effective date.

OK SB359

Motor vehicles; allowing Service Oklahoma to provide a list of open recalls for vehicles with motor vehicle registration and notify certain vehicle owners. Effective date.

OK SB135

Aeronautics technology; modifying Oklahoma Aircraft Engine Testing Development Grant Program; expanding purpose of certain program; depositing certain monies in certain fund. Effective date. Emergency.

Similar Bills

No similar bills found.