Verification of GHG Emissions Data Reports

This page last modified July 28, 2016

The Regulation for the Mandatory Reporting of Greenhouse Gas Emissions (reporting regulation or MRR) requires the independent verification of greenhouse gas (GHG) emissions data reports.   Verification questions may be sent to  Information about the Offset Verification Program is provided at:

MRR Regulation (with referenced version of U.S. EPA's 40 CFR Part 98)

Cap-and-Trade Regulation


The reporting regulation was developed under the California Global Warming Solutions Act of 2006 (Statutes of 2006; Chapter 488; Health and Safety Code sections 38500 et seq.) and approved by the California Air Resources Board (ARB or Board) in December 2007, with subsequent amendments in 2010, 2012, 2013, and 2014.  The 2014 MRR revisions became effective on January 1, 2015.  The requirements for independent verification of emissions data reports and ARB oversight of accreditation were included in the original regulation and are consistent with international best practices.  The MRR is codified in Subchapter 10, Article 2, sections 95100 to 95158, title 17, California Code of Regulations.

Latest News

Six-Year Verifier Time Limit
The six-year time limit to prevent conflict of interest (MRR section 95130(a)(2)) will affect over ten percent of verifications performed for the 2015 data reporting year. ARB will not approve COI assessments for cases where the six-year limit does not allow sufficient time to complete verification services. If the six-year expiration is less than 60 days after the reporting deadline, verification services cannot proceed unless a credible verification plan is reviewed and accepted by ARB. Emissions data reports that are not verified by the six-year expiration date must be reverified by another verification body by September 1, 2016, and ARB will consider suspension or revocation of accreditation.

Information for Verifiers

Questions regarding ARB accreditation and verification should be sent to
Verification Body Application for Accreditation/Reaccreditation
Application for Verifier Reaccreditation (an application must be submitted for existing accredited verifiers)
Conflict of Interest (COI/NOVS) Form
Verification Statement Form (for use with all reporting entities except petroleum refineries)
Petroleum Refinery Verification Statement Form (for use with petroleum refineries only)

Information for Reporting Entities

Reporting entities are required to have their GHG emissions data reports verified each year by an ARB-accredited verification body, beginning in 2010 for 2009 emissions. The third-party verification requirements and deadline are specified in section 95103(f) of the reporting regulation. Compliance dates are summarized at:

Only ARB-accredited verification bodies and verifiers may provide verification services to reporting entities. The following web link provides a list of ARB-accredited verification bodies and additional information:

On April 24, 2013, a webinar titled "Tips for a Successful Verification" was given to emissions data reporters.  A link to the presentation is here.