October 19, 2016. An email from someone within the regulated community:

40# Jerricans are placed in an enclosure. The enclosure consists of 4 walls 4′ high 4’across and 4′ wide. The walls can be disassembled from around the Jerricans. Would walls that can be disassembled from around these packages be considered a container, package, or enclosure? Would this assembly be considered a container, package, or enclosure? Thank you.

Note:  Per 49 CFR 171.8, Jerrican means a metal or plastic packaging of rectangular or polygonal cross-section.

My reply that same day:

I will attempt to answer your question. Please see below.

• I assume the 40# Jerricans are the authorized packaging for a hazardous material, they meet the DOT specifications and are marked to show this, and have all the required HazMat labels and markings.
• If the above is true, then anything you use to enclose the jerricans meets the definition of an overpack. What you describe is acceptable as an overpack. You can read more about an overpack (and a salvage drum) in this article I wrote for New Pig: Salvage Packaging vs. Overpacks: What’s the difference?
• All HazMat labels and markings on the jerricans must be visible on the outside of the overpack along with the word “Overpack”. Labels and markings should appear on at least two opposing sides of the overpack.
• For the purposes of the USDOT regulations it would be considered an Overpack. Other terms (container, package, or enclosure, &etc.) don’t apply.

I hope this helps.

Please don’t hesitate to contact me with any other questions.

My answer appeared to satisfy him (10.22.16):

Thank you so much!

The use of an overpack in the transportation of hazardous materials should be a simple thing, but it isn’t.  Some of this is due to the confusion between the terms “overpack” and “salvage packaging”; a confusion I tried to clear-up in my above-referenced article.  Some is due to a hesitancy on the part of the shipper or reluctance on the part of the carrier to deal with this additional requirement of shipping a hazardous material.  Whatever your concern, contact me if you have any questions about the use of an overpack for the transportation of your hazardous materials.