No, for the testing of fuel for compliance with the 15 ppm sulfur standard, we do not consider the two approaches to be equivalent. The second approach listed is not an option for approval of a test method under the diesel fuel regulations, and therefore testing with methods not approved under § 80.581 and § 80.585 would not be considered an adequate defense to presumptive liability.
Test results from test methods that have not been approved under the regulations might be considered as evidence of compliance or noncompliance with the standard, but use of the unapproved method would not be considered as meeting the periodic sampling and testing requirement for defense purposes; nor would use of an unapproved method be considered to have fulfilled the requirement for refiners and importers to test every batch. Testing for 500 ppm fuel has a different situation.
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)