An independent lab may use a second lab to collect samples or perform required tests, provided that:
(1) the second lab is independent as defined in § 80.65(f)(2)(iii);
(2) the primary independent lab is responsible for the quality of work performed by the second independent lab; and
(3) the primary independent lab remains responsible for receiving all communications from EPA and submitting all reports to EPA.

If a second independent lab is used, there is no requirement to report this fact to EPA, but the primary independent lab should retain documents to support the manner in which the sample collection and analyses were performed. Such documents then would be available, at the time of the independent attest engagement or EPA audit, to document the proper completion of the independent sampling and testing requirements.(7/1/94)

This question and answer was posted at Consolidated List of Reformulated Gasoline and Anti-Dumping Questions and Answers: July 1, 1994 through November 10, 1997 (PDF)(333 pp, 18.17 MB, EPA420-R-03-009, July 2003, About PDF)