Clarification of the Inspection and Retest Requirements

This is in reference to your letter dated May 5, 1992, requesting clarification of the inspection and retest requirements for non specification vacuum-loaded cargo tanks manufactured under various DOT exemptions. These cargo tanks are used to transport flammable liquid, corrosive and Poison B waste materials.

As specified in the exemptions, vacuum-loaded cargo tanks must be designed constructed in full conformance with the MC 307 or MC 312 cargo tank specification, with certain exception, and be tested and inspected as prescribed for the applicable specification. As you are aware, the test and inspection frequency for MC 307 and MC 312 cargo tanks has been increased fro what was previously a two-year schedule. Section 177.824 requires all specification cargo tank motor vehicles to be tested and inspected as prescribed in 49 CFR Part 180. The vacuum-loaded waste cargo tanks authorize under exemptions are Subject to the test and inspection schedule contained in § 180.407(c), instead of the previous two-year schedule.

Some exemptions have been updated to reference requirements in Part 180. We will take action to inform all exemption holders of the applicable requirements. Also, as these vacuum-loaded cargo tanks are retro-fitted to conform to the applicable specification and remarked as specification cargo tanks, as required by § 180.405(f), confusion concerning inspection and retest of these tanks should be alleviated.

We appreciate your bringing this matter to our attention.