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. Regulations for Emissions from Vehicles and Engines

Final Rule for Emergency Vehicle Rule - Selective Catalytic Reduction (SCR) Maintenance and Regulatory Flexibility for Nonroad Equipment

Final Rule for Emergency Vehicle Rule - Selective Catalytic Reduction (SCR) Maintenance and Regulatory Flexibility for Nonroad Equipment
Basic Information
Code of Federal Regulations Citations
  • 40 CFR Part 86
  • 40 CFR Part 1039
Docket Numbers
  • EPA-HQ-OAR-2011-1032

On this page:

  • Rule Summary
  • Rule History
  • Additional Resources

Rule Summary

Related Regulations

Direct Final Rule for Heavy-Duty Highway Program: Revisions for Emergency Vehicles

This rule consists of three parts. First, the Environmental Protection Agency (EPA) is adopting minimum maintenance intervals for replenishment of consumable chemical reductant (commonly known as diesel exhaust fluid, or DEF) in connection with the use of selective catalytic reduction (SCR) technologies. Second, EPA is adopting provisions allowing manufacturers of nonroad engines to give operators the means to obtain short term relief from emission controls while operating in emergency situations, such as those where operation of a nonroad engine or equipment is needed to protect human life, and where obtaining short-term relief from emission controls enables such operation. Third, EPA is adopting minor revisions to the direct final rule for emergency vehicles that became effective August 7, 2012, in response to comments received on the parallel Notice of Proposed Rulemaking.

  • Final Rule: Emergency Vehicle Rule—SCR Maintenance and Regulatory Flexibility for Nonroad Equipment (pdf) (323 KB, published August 8, 2014)
  • Summary and Analysis of Comments: Emergency Vehicle Rule — SCR Maintenance and Regulatory Flexibility for Nonroad Equipment: (pdf) (256 KB, EPA-420-R-14-001, July 2014)

Rule History

  • Proposed Rule and Related Materials

Additional Resources

  • Fact Sheet: EPA Sets Standards for Diesel Fluid Systems; Adopts Relief Measures for Nonroad Equipment (pdf) (133 KB, EPA-420-F-14-017, July 2014)

Regulations for Emissions from Vehicles and Engines

  • Onroad
    • Passenger Vehicles
    • Commercial Trucks & Buses
    • Motorcycles
  • Nonroad
    • Aircraft
    • Heavy Equipment
    • Locomotives
    • Marine
    • Recreational Vehicles
    • Small Equipment & Tools
  • Greenhouse Gas
Contact Us About Regulations for Emissions from Vehicles and Engines
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on May 12, 2025
  • 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.