California Air Resources Board

California Multimedia Evaluation of E10-E15 Gasoline-Ethanol Blends Tier II Report 

Prepared by Ecoengineering, Inc. for the Renewable Fuels Association and Growth Energy

The California Health and Safety Code (HSC 43830.8) requires that a multimedia evaluation (MME) be conducted and reviewed by the California Environmental Policy Council (CEPC) before specifications for new motor fuels can be adopted by the California Air Resources Board (CARB). The purpose of the MME is to develop information that will enable the CEPC to determine whether a new fuel specification would cause any significant adverse impacts to public health or the environment.  

Tier II is the second step in the three-tier MME process. The Tier II Report presents the testing procedures and results that addressed the data gaps identified during Tier I. The Tier I Report is available at:  California Multimedia Evaluation of E11-E15 Gasoline-Ethanol Blends Tier I Report.   

As a part of the MME for E15, CARB contracted with the University of California at Riverside (UCR) Bourns College of Engineering – Center for Environmental Research and Technology (CE-CERT) to evaluate exhaust emissions from the use of California Reformulated Gasoline (CaRFG) that contains 15 volume percent ethanol (E15).  Two fuels (E10 and E15) were tested on twenty vehicles (2016 and newer gasoline-fueled) over triplicate Federal Test Procedure (FTP) cycles. The report is available at:  Comparison of Exhaust Emissions Between E10 CaRFG and Splash Blended E15. 

CARB continues to prioritize the expeditious review of the MME process as directed by Governor Newsom in his letter to CARB on October 25, 2024. The letter is available at: 10.25.24-letter-to-CARB.pdf.

Comparison of Exhaust Emissions Between E10 CaRFG and Splash Blended E15 

submitted by the University of California, Riverside College of Engineering – Center for Environmental Research and Technology (June 2022) 

California Multimedia Evaluation of E11-E15 Gasoline-Ethanol Blends Tier I Report  

prepared by Growth Energy and the Renewable Fuels Association (June 2020)