EPA announces updated vehicle and engine tampering policy

The U.S. Environmental Protection Agency (EPA) recently released a long-awaited update to its enforcement policy on vehicle and engine tampering and aftermarket parts.

The “EPA Enforcement Policy on Vehicle and Engine Tampering and Aftermarket Defeat Devices under the Clean Air Act” (Tampering Policy), dated November 23, 2020, supersedes and replaces the prior enforcement memorandum, the Mobile Source Enforcement Memorandum 1A, which had been in place since 1974, as well as other related guidance documents. The Tampering Policy reaffirms EPA’s practice of not pursuing enforcement actions for potential tampering or defeat device violations under the Clean Air Act (CAA) if the person engaging in the conduct has a “documented, reasonable basis to conclude that the conduct does not adversely affect emissions.” The Tampering Policy does, however, include a number of changes of which those in the industry should be aware.

The revised Tampering Policy provides:

The EPA typically does not take enforcement action for conduct that might be a violation of section 203(a)(3) of the Clean Air Act if the person engaging in the conduct has a documented “reasonable basis” to conclude that the conduct (or, where the conduct in question is the manufacturing or sale of a part or component, the installation and use of that part or component) does not and will not adversely affect emissions. This Policy Statement does not apply, however, to conduct affecting an OBD system, which may be subject to enforcement regardless of effect on emissions.

The Tampering Policy then lists six ways that a person may document such a “reasonable basis,” which is meant to be illustrative rather than exhaustive:

  1. Identical to Certified Configuration
  2. Emissions Testing for Replacement Aftertreatment Systems for Older Vehicles, Engines, and Equipment
  3. New Aftertreatment Systems that Decrease Emissions
  4. Emissions Testing
  5. EPA Certification of Aftermarket Part
  6. California Air Resources Board Exemption of Aftermarket Part

The Tampering Policy effectively creates new expectations regarding documentation of the “reasonable basis.” EPA clarifies that it expects documentation of such a “reasonable basis” to exist at or before the time the conduct that may violate the CAA occurs. EPA explains that this conduct could include the sale of a product, installation of a product, or service on a vehicle. Accordingly, the reasonable basis justification cannot be developed after the fact. Further, in determining whether a “reasonable basis” exists that the conduct does not adversely affect emissions, the Tampering Policy provides that the relevant comparison will be made between the component’s condition after service and the component’s original certified configuration, rather than the component’s condition immediately prior to service.

Although the Tampering Policy emphasizes that EPA retains its enforcement discretion in all cases and considers each case independently, including relevant case-specific facts and circumstances, manufacturers should carefully review their business practices in light of the updated Tampering Policy.

Importantly, the Tampering Policy makes clear that it does not address vehicles originally built for non-road competitive use, vehicles that are converted for use solely in competition motorsports, or aftermarket parts purportedly manufactured or sold for those purposes. The Tampering Policy also does not apply to potential tampering or defeat device violations by original equipment manufacturers (OEMs) and does not affect any person’s obligation to comply with state and local laws.

In conjunction with the release of the updated Tampering Policy, EPA issued a notice and Request for Information Relevant to the 1986 Catalyst Policy that addresses the manufacture, sale, and installation of replacement catalytic converters. Pursuant to the 1986 Catalyst Policy, EPA generally does not pursue enforcement action for the manufacture, sale, or installation of a replacement catalyst (even a less effective catalyst) so long as it meets certain performance criteria. EPA seeks input regarding its ongoing evaluation of the 1986 Catalyst Policy, including a future decision to potentially update or withdraw the policy. EPA will accept comments submitted within 60 days of publication of the Notice in the Federal Register, which is expected in the next two weeks. Those with business interests in replacement catalytic converters should review and consider whether they need to comment prior to this deadline.

We welcome the opportunity to work closely with you to navigate how the revised Tampering Policy and potential changes to the Catalyst Policy could impact your business.

This alert was authored by Joanne Rotondi, Jennifer Adams, Hannah Graae, and Katie Lannon.

Jennifer Adams
Joanne Rotondi
Washington, D.C.
Hannah Graae
Senior Associate
Washington, D.C.
Katie Lannon
Senior Associate
Washington, D.C.


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