An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Fuels Registration, Reporting, and Compliance Help

Will there be an allowance for other additives in ULSD with a sulfur content greater than 15 ppm? like cetane enhancer?

Additives with a sulfur content greater than 15 ppm may be added by terminals to diesel fuel that is subject to the 15 ppm sulfur standard, provided that the terminal ensures that the finished fuel blend remains compliant with the 15 ppm sulfur standard. To meet their affirmative defenses to presumptive liability, terminals that use above 15 ppm additives in ULSD typically must conduct a sulfur test on the finished fuel post-additization (see 40 CFR 80.613(a)(1(vi)).

Conductivity additives and the red dye used to comply with Internal Revenue Service (IRS) requirements currently can not be manufactured with a sulfur content less than 15 ppm. We did not want the standard affirmative defense provisions (of § 80.613) to present a barrier to the use of conductivity additives and red dye.

Therefore, EPA instituted alternative affirmative defense provisions regarding the use of these additives (through technical amendments to the regulations in May 2006, at § 80.614) that are based on volumetric accounting reconciliation and a sulfur test prior to additization. For other diesel fuel additive types, there are currently additives available that comply with the 15 ppm sulfur specification. Thus, alternative affirmative defense provisions are not needed for additives other than red dye and conductivity additives.

Question and Answer was originally posted at Questions and Answers on the Clean Diesel Fuel Rules (PDF)(135 pp, 888 K, EPA420-B-06-010, July 2006, About PDF)