The possible designations for #1 and #2 distillate are detailed in § 80.598. An entity would have the option to designate it as heating oil or blendstock if it did not want to comply with the highway and NRLM standards.
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)