Removing the Confusion Over Scuba Cylinder Transportation in the United States

by Rob Bradish:

Over the years the subject of the transportation of scuba cylinders has come up numerous times. A sore spot however, is that the writer rarely provides references to a particular law when defining a responsibility. Over time, I have discovered that much of this has to do with information passed on verbally and subsequently becoming tribal. That information likely started out as accurate, but over the course of time, similar to the “Telephone Game” that information has swayed slightly from the original path!

The first level of understanding needs to be that a pressurized scuba cylinder is considered Hazardous Material (HazMat) by governing bodies of these United States, including the Department of Transportation (DoT). Specifically, DoT references scuba cylinders as Class 2 HAZMAT material, as defined by CFR173.115(b)(2) which states:

(b) Division 2.2 (non-flammable, nonpoisonous compressed gas—including compressed gas, liquefied gas, pressurized cryogenic gas, compressed gas in solution, asphyxiant gas and oxidizing gas). For the purpose of this subchapter, a non-flammable, nonpoisonous compressed gas (Division 2.2) means any material (or mixture) which—

(1) Exerts in the packaging a gauge pressure of 200 kPa (29.0 psig/43.8 psia) or greater at 20 °C (68 °F), is a liquefied gas or is a cryogenic liquid, and

(2) Does not meet the definition of Division 2.1 or 2.3.

In simple terms, if transporting scuba cylinders with more than 29.0 psig, then the regulations may apply to you!

Before we can get into what regulations may not apply, we have to set the bar. The bar is set at 1000 pounds of total weight or greater. At that point, for all but a select few, commercial guidelines apply which include: who may be licensed to transport the cylinders; how it may be done; and appropriate markings, or placards that are required. Much of this information may be found in CFR172.500, and more specifically 172.528 for Non-Flammable Gas, and 172.530 for Oxygen.

Recreational Divers

The next point has to do with the word commerce. If someone is transporting less than 1000 pounds, and there is no commerce involved, than you are exempt from other rulings. This means a recreational diver, or group of recreational divers, headed to a dive site with scuba cylinders for themselves and their use is exempt from any rulings. A lot of people like to use this as a get out of jail card, but there can be caveats. For example, if that same group is bringing a rental cylinder for a buddy, that group could then be considered an agent for the Dive Center, changing things altogether.

Commercial Divers

Divers who use scuba cylinders as a matter of their job function, even though performing commerce, could be provided with an exemption as well. Under CFR173.6, there is an exemption granted for use as Materials of Trade. This exemption allows the user to carry up to 440 pounds of cylinders (~8-10 full scuba cylinders) to use as a function of his job, allowing a salvage diver, pool worker, or boat bottom cleaner to function without the need of creating shipping papers every day. The caveat here is that the cylinders be considered for his or her personal use as a part of the job function.

Instructors and Dive Centers

So, a whole bunch of instructors and Dive Centers are looking at CFR173.6 and thinking that should apply to them. Sadly, the DoT disagrees. Because the instructor is transporting cylinders for use by the student, and not for personal use, the Materials of Trade exemption does not apply. This rule even applies to colleges and universities who teach scuba diving as a part of their Paid For programs. At this stage, in accordance with CFR172.201, all cylinders must be clearly marked with the contents of the cylinder, and shipping papers need to be utilized. Shipping papers can vary from state to state but the basic content is the same and includes:

  • Shipper Date
  • Emergency Contact Number (other than a number of the person(s) in the transport vehicle)
  • Quantity of each HazMat Item being Transported (One Cylinder, One Item)
  • United Nations HazMat Code (Chart in CFR172.101)
    • Air- “Air, Compressed, 2.2/UN1002”
    • O2 Rich (Over 23.5% O2)-“Compressed Gas, Oxidizing, NOS 2.2/UN3156”
    • O2- “Oxygen, Compressed, 2.2/UN1072” (That Pesky O2 Kit)
    • TriMix (under23.5% O2)- “Compressed Gas, NOS, 2.2/UN1956”

These papers need to be kept in the transporting vehicle, as well as on location with the Emergency contact. Additionally, after transport, these papers need to be kept on file for a period of one year.

For specific details about shipping papers for your state, contact your local State Department of Transportation.

ERD Teams

Emergency Response teams fall under the ultimate exemption. As a government entity, Law Enforcement and Fire Departments fall under a totally different set of guidelines and are subsequently exempt for these rulings. This allows them to transport gear via fire trucks, response team trailers and other such equipment

As you can see, there is room for confusion around these regulations, but by referencing the appropriate CFR you can work through the best course of action to transport your scuba cylinders legally and safely!!! Special thanks go to Director, John Heneghan and Inspector, Stuart Streck of the Department of Transportation Field Services Support Team, Southern Region for helping navigate the numerous rulings and clarifying some points.

For more information or to research for yourself, please consider the following resources:

For those of you outside of the United States, we advise you familiarize yourselves with the local laws and regulations governing the transportation of scuba cylinders in your area.

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