Parties in the distribution chain downstream of the refiner or importer are not required to test motor vehicle diesel fuel. However, in order to establish a defense to any violation, downstream parties must conduct a quality assurance program, including sampling and testing.

The fuel must meet the standard on a per-gallon basis. An appropriate field method may be used for downstream quality assurance testing. The regulations do not specify which testing method must be used for downstream quality assurance testing.

The sampling methods prescribed by the rule in § 80.580 would be appropriate for purposes of quality assurance sampling under § 80.613(d)(1).

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)