Invalid Hydro Stamps on Scuba Cylinders

The Department of Transportation is seeking assistance from divers to identify Scuba Cylinders with an invalid Retesters Identification Number (RIN).  The RIN is applied after hydrostatic testing, which must be performed every five years to ensure Scuba Cylinders are in a safe condition.  It identifies which facility performed the hydrostatic test.  Each facility performing these tests is required to be licensed and verified to ensure public safety in the testing and handling of Scuba Cylinders.

An image of the invalid RIN is below, and appears as the letter “C” over the letter “L” stamped between the month and year of hydro testing.  Reports indicate that the Scuba Cylinders identified were sold second-hand off of eBay or Craigslist – yet another reason to avoid purchasing this life support equipment from other than reputable dealers.


The Department is attempting to locate the place where cylinders bearing this marking were tested, and asking anyone who is in possession of a cylinder with this improper RIN (or knows where one is) to contact them immediately.  If you find a tank with this marking, please immediately contact Earl Whitley at or 909-222-9546.

One tank with such markings has already been located in Hawaii and another is known to be in California.

If you are in possession of this cylinder or one without a proper requalification marking, please ensure that it is tested before being placed into service.

Further information regarding cylinders can be found at

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