Illinois Statutes Chapter 815. Business Transactions § 370/4. ASTM standards

(a) All motor fuel and petroleum sold or offered for sale in the State of Illinois shall conform to the standards of this Act. The standards set forth in the Annual Book of ASTM Standards Section 5, Volumes 05.01, 05.02, 05.03, 05.04 and 05. 05 and supplements thereto, and revisions thereof are adopted unless modified or rejected by a regulation adopted by the Department. In addition, any advertised or labeled declarations regarding the quality of a motor fuel which are more stringent than ASTM standards shall be met.

(a-5) The quality of gasoline-oxygenate blends sold or offered for sale in this State shall meet the standards set forth in Section 2.1.1.1 or Section 2.1.1.2 of the Uniform Engine Fuels, Petroleum Products, and Automotive Lubricants Regulation as provided under the National Institute of Standards and Technology Handbook 130, and any of its subsequent supplements or revisions, except as specifically modified, amended, or rejected by regulation issued by the Director.

(b) Minimum Automotive Gasoline Octane Requirements.

All leaded and unleaded gasoline sold in this State shall meet or exceed the following minimum octane numbers:

Regular Grade 87

Midgrade or Plus 89

Premium or Super Grade 91

An octane number is determined by adding the research octane number to the motor octane number and dividing by 2. (RON + MON)/2. In addition, the motor octane number shall not be less than 82.0. All gasoline products sold at retail shall have an octane number displayed.

(c) Each seller of a motor fuel shall notify the purchaser of the type and quantity of motor fuel purchased. For gasoline, the type shall indicate the octane number. This information shall appear on the bill of lading, manifest, or delivery ticket for the fuel. This subsection does not apply to sales at retail.

(d) All gasoline products shall meet the most recently adopted ASTM standards for spark-ignition motor fuel, and those standards adopted under the provisions of the federal Clean Air Act  1 by the U. S. Environmental Protection Agency shall be the standards of this State in those areas in which the federal Clean Air Act fuel standards apply.

(e) All biodiesel with a numerical value of B99 or above that is sold or offered for sale in the State of Illinois shall conform to the ASTM D6751 Standard Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels. For the purposes of this subsection (e), “Biodiesel” means a fuel that (i) is comprised of mono-alkyl esters of long-chain fatty acids derived from vegetable oils or animal fats and (ii) meets the requirements of the ASTM D6751 standards.