Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

HTTPS

Secure .gov websites use HTTPS
A lock (LockA locked padlock) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

    • Environmental Topics
    • Air
    • Bed Bugs
    • Cancer
    • Chemicals, Toxics, and Pesticide
    • Emergency Response
    • Environmental Information by Location
    • Health
    • Land, Waste, and Cleanup
    • Lead
    • Mold
    • Radon
    • Research
    • Science Topics
    • Water Topics
    • A-Z Topic Index
    • Laws & Regulations
    • By Business Sector
    • By Topic
    • Compliance
    • Enforcement
    • Laws and Executive Orders
    • Regulations
    • Report a Violation
    • Environmental Violations
    • Fraud, Waste or Abuse
    • About EPA
    • Our Mission and What We Do
    • Headquarters Offices
    • Regional Offices
    • Labs and Research Centers
    • Planning, Budget, and Results
    • Organization Chart
    • EPA History

Breadcrumb

  1. Home
  2. Compliance

Mobile Sources Compliance Monitoring Program

Compliance with the vehicle and engine emissions standards is the responsibility of the vehicle or engine manufacturer. Vehicles and engines used in the United States must be manufactured under the terms of an emissions certificate of conformityThe document issued to a motor vehicle or motor vehicle engine manufacturer by EPA under section 206(a) of the Act. A Certificate of Conformity certifies that a particular class of motor vehicle conforms to the EPA requirements. Every class of motor vehicle introduced into U.S. commerce must have a Certificate of Conformity which is valid for only one model year of production. issued by EPA.  Imported vehicles and engines must be EPA-certified, with certain very limited exceptions. The removal or disabling of vehicle or engine emission controls by any person is prohibited.

Refiners and fuel importers have the primary responsibility of compliance with the motor vehicle fuels standards. Parties in the fuel distribution system are responsible for ensuring that motor vehicle fuel is not contaminated and is used in the proper locations and times.  For example, more stringent gasoline standards apply during the summer high ozone season and to reformulated gasoline used in certain ozone nonattainment areas. Vehicles and equipment may only use fuels designated and registered for that type of vehicle or equipment.

Compliance Monitoring

EPA reviews applications for emissions certificates from vehicle and engine manufacturers, and conducts emissions testing of vehicles and engines on the production line and in-use following introduction into commerce. EPA works in conjunction with the United States Customs and Border Protection to ensure that imported vehicles and engines are certified. In addition, light-duty vehicle emissions are checked periodically through state-implemented “inspection and maintenance” programs in most ozone nonattainment areas. EPA conducts inspections of:

  • vehicle and engine manufacturing facilities,
  • emission laboratories,
  • dealers of vehicles and mobile engines and
  • suppliers and installers of vehicle and engine parts.

EPA conducts fuels inspections primarily at:

  • retail outlets
  • terminals
  • refiners
  • importers
  • fuels testing laboratories

Refiners and importers are required to test all their gasoline and submit reports to EPA. In addition, refiners and importers are required to use independent laboratories to conduct quality assurance testing of reformulated gasoline when it is produced and quality surveys of reformulated gasoline when it is sold at retail outlets, and to submit reports to EPA of this testing.

Compliance

  • Addressing Noncompliance
    • How We Monitor Compliance
    • Compliance Monitoring Programs
      • CAA
      • CERCLA
      • CWA
      • FIFRA
      • RCRA
      • SDWA
      • TSCA
    • Audit Policy
    • Compliance Monitoring Resources and Guidance Documents
  • Assisting Regulated Entities
    • Compliance Assistance Centers
    • Compliance Advisors
    • Compliance Assistance Resources and Guidance Documents
  • Training EPA and its Partners
    • National Enforcement Training Institute (NETI)
  • Engaging State and Tribal Partners
    • State Review Framework
    • State Oversight Resources and Guidance Documents
  • Advancing EPA's National Planning and Results
    • Compliance Learning Agenda
  • Compliance Assurance Data Tools
    • NPDES Electronic Reporting
Contact Us about Compliance
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on October 30, 2024
  • Assistance
  • Spanish
  • Arabic
  • Chinese (simplified)
  • Chinese (traditional)
  • French
  • Haitian Creole
  • Korean
  • Portuguese
  • Russian
  • Tagalog
  • Vietnamese
United States Environmental Protection Agency

Discover.

  • Accessibility Statement
  • Budget & Performance
  • Contracting
  • EPA www Web Snapshot
  • Grants
  • No FEAR Act Data
  • Plain Writing
  • Privacy
  • Privacy and Security Notice

Connect.

  • Data
  • Inspector General
  • Jobs
  • Newsroom
  • Regulations.gov
  • Subscribe
  • USA.gov
  • White House

Ask.

  • Contact EPA
  • EPA Disclaimers
  • Hotlines
  • FOIA Requests
  • Frequent Questions
  • Site Feedback

Follow.