The United States Pipeline and Hazardous Materials Safety Administration (“PHMSA”) addressed a question posed by GEODynamics Inc. (“GI”) relating to an “overpack” under the Hazardous Materials Regulations (“HMR”) in an August 18th letter.

GI in a March 3rd letter described a scenario involving non-bulk packages of Division 1.4D explosives that are shrink-wrapped together on a warehouse skid. The company further notes that the packages are covered by § 172.504(e), Table 2, and have an aggregate gross weight over 1,001 lbs.

GI asked whether the tarpaulin cover required by § 177.835(h) is considered an overpack, as defined in § 171.8, and therefore subject to the provisions of § 173.25.

PHMSA states the answer is no. It further notes:

The tarpaulin required by § 177.835(h) is considered environmental protection and is not an overpack. Likewise, if all the required marks and labels are visible on the packages through the shrink-wrapped skid protected by the tarpaulin cover, no further action is necessary. If any of the required marks and labels are not visible on the packages through the shrink-wrap, the shrink-wrapped skid is considered an overpack and is required to be marked and labeled for every shipping description in the overpack as prescribed in § 173.25(a)(2). Further, as prescribed in § 173.25(a)(4), the word “OVERPACK” is only required to be marked on the shrink-wrapped skid if package specification markings, when required, are not visible through the shrink wrap.

A copy of the letter can be downloaded here.