Scubapro First Stage Explodes: Eleven-Year-Old Recall Notice Missed

Maxine Barrett (Los Angeles, CA) wrote to tell us that the Mk10 first-stage of her Scubapro regulator blew up! It was attached to an aluminum 80, 3000 psi (205 bar) tank that was being held by a divemaster before Barrett donned it. Luckily, the divemaster was behind the tank when the first-stage blew, and Barrett had not yet entered the water. Nobody was injured.

The regulator, having been serviced yearly for more than 10 years, had been serviced the week before the rupture. Barrett had made two dives a day with it before it exploded. She asked whether we had seen this kind of damage before and what might have caused it.

Now, we hadn't seen that before, so Undercurrent contacted Gilbert de Coriolis, the Technical Director for Global Diving for Johnson Outdoor (Scubapro). He told us they discovered the problem long ago, and, in fact, said they had recalled the Mark 20 first-stage in 2006 because of it.

The first stage rupture "was caused by a combination of repeated over-torqueing of the DIN wheel or Yoke retainer and the action of salt water in a micro crack that developed. We recommended more than 35 years ago the compulsory use of a torque wrench when carrying out maintenance on our products, but many technicians over-torque parts. They should not exceed 30 Newtons/meter." (A Newton is a measurement of force.)

He told Undercurrent that, in order to rupture the body, a technician must apply pressure greater than 120 Newtons/meter. After the 2006 recall, Scubapro modified the DIN and Yoke retainers, adding a shoulder to prevent over-torqueing. This shoulder takes the overload and distorts to save the body if one tries to over-tighten.

It appears that Maxine Barrett's regulator had both missed the recall and been (possibly repeatedly) subject to heavy-handed servicing that weakened the unit and led to the rupture.