211B Research Group
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THE 211(b) RESEARCH GROUP

The Research Group was formed to help fulfill the post-1994 211(b) requirements for gasoline and diesel fuel. The group’s main purpose is to meet testing requirements under Tier 1 and Tier 2 for two of the three main fuel categories. The Research Group does not address atypical fuels that contain elements other than carbon, hydrogen, oxygen, nitrogen, and sulfur. The Research Group sponsored research and several literature reviews that were used in comments to EPA for development of an Alternative Tier 2 testing program.

To help fulfill the new Section 211(b) requirements for gasoline and diesel fuel, the American Petroleum Institute organized the 211(b) Research Group (“Research Group”).  The Research Group is an unincorporated group of fuel, oxygenate, and fuel additive manufacturers affiliated by contractual obligation with the purpose of meeting the Tier 1 and Tier 2 testing requirements of Section 211(b)(2) and 211(e) of the Clean Air Act. The Research Group will not address potential testing required under Tier 3.

The Research Group’s purpose is to address two of the three fuel categories for the conventional fuel families (Gasoline and Diesel) as outlined in the 211(b) Rule (40 CFR 79.56 – see table below).  The Research Group does not address the alternative fuel families: Methanol, Ethanol, Methane, and Propane.  Membership in the Research Group is open to any company that has an interest in the registration of these products with EPA.  The Research Group tested:

  1. “Baseline” Fuel Groups
    • This fuel group contains no elements other than carbon, hydrogen, oxygen, nitrogen, and sulfur.
    • Gasoline contains less than 1.5% oxygen by weight
    • Diesel contains less than 1.0% oxygen
  2. “Non-baseline” Fuel Groups
    • This fuel group contains only the elements listed above but are either derived from nonconventional sources of oil, or contain in excess of 1.5% or 1.0% oxygen by weight for gasoline and diesel respectively.
    • Oxygenates in non-baseline fuel groups tested by the Research Group were: methyl tertiary-butyl ether (MTBE), ethanol (EtOH), ethyl tertiary-butyl ether (ETBE), tertiary-amyl methyl ether (TAME), di-isopropyl ether (DIPE) and tertiary-butyl alcohol (TBA).

The Research Group's testing scope does not include a third category of fuel groups, the atypical fuel groups, which consist of fuels or fuel additives that contain elements other than carbon, hydrogen, oxygen, nitrogen and sulfur.

The Research Group sponsored research and several literature reviews that were used in comments to EPA for development of an Alternative Tier 2 testing program.  The original rule required health effects testing in rodents on diesel and gasoline exhaust emissions as well as gasoline evaporative emissions.  The Research Group sought to modify the final rule in each of these areas.

  • Diesel exhaust emissions: The Research Group felt there was adequate existing data on diesel exhaust for all the required endpoints (Research Group, 1996).   EPA agreed and dropped that requirement from the Alternative Tier 2 Testing Program (EPA Docket, 1998a).  
  • Gasoline exhaust emissions: The Research Group felt there was no value in testing rodents for effects of engine-out gasoline emissions primarily because of the carbon monoxide content of the exhaust.  The toxicology of carbon monoxide is well studied and would obscure the effects of other exhaust components (Barter et al., 1996; Docket item, A-96-16/II-D-1).  EPA agreed and dropped that requirement from the Alternative Tier 2 Testing Program (EPA Docket, 1998a).
  • Gasoline evaporative emissions: A method to generate the test article used in rodent testing was developed as an alternative to the methodology outlined in the original 211(b) rule (FR June 27, 1994).  The Research Group developed and demonstrated an alternative method where the test article was fabricated at a central facility and was more similar in composition to the evaporative emissions from an automotive fuel tank at near maximum in-use temperatures (Chevron, 1997).  EPA approved the Research Group’s proposed methodology as part of their Alternative Tier 2 Rulemaking (EPA Docket, 1998b).

Fuel Families in the Clean Air Act (40 CFR 79.56) Emphasizing the Fuels and Categories Addressed by the 211(b) Research Group

Category Gasoline (A) Diesel (B) Methanol (C) Ethanol (D) Methane (CNG, LNG) (E) Propane (LPG) (F)
Baseline One group represented by gasoline base fuel. One group represented by diesel base fuel. Two groups: (1) M100 group (includes methanol-gasoline formulations with at least 96% methanol) represented by M100 base fuel (2) M85 (includes methanol-gasoline formulations with 50–95% methanol) represented by M85 base fuel. One group (includes ethanol-gasoline formulations with at least 50% ethanol) represented by E85 base fuel. One group (includes both CNG and LNG), represented by CNG base fuel. One group represented by LPG base fuel.
Non-baseline One group for each gasoline-oxygenate blend or each gasoline-methanol/co-solvent blend; one group for each synthetic crude-derived fuel. One group for each oxygen-contributing compound or class of compounds; one group for each synthetic crude-derived fuel. One group for each individual non-methanol, non-gasoline component and one group for each unique combination of such components. One group for each individual non-ethanol, non-gasoline component and one group for each unique combination of such components. One group to include methane formulations exceeding the specified limit for non-methane hydrocarbons. One group to include propane formulations exceeding the specified limit for butane and higher hydrocarbons.
Atypical One group for each atypical element/characteristic, or unique combination of atypical elements/characteristics. One group for each atypical element/characteristic, or unique combination of atypical elements/characteristics. One group for each atypical element/characteristic, or unique combination of atypical elements/characteristics. One group for each atypical element/characteristic, or unique combination of atypical elements/characteristics. One group for each atypical element/characteristic, or unique combination of atypical elements/characteristics. One group for each atypical element/characteristic, or unique combination of atypical elements/characteristics.
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