A Victorian dive company has been fined $40,000 after an exploding scuba cylinder severed an instructor’s leg and caused significant building damage.

Stelkea, trading as Australian Diving Instruction, was sentenced without conviction at Geelong Magistrates’ Court after pleading guilty to one charge of failing to provide a safe workplace. The company must also pay costs of $4386.

A volunteer dive instructor was filling scuba cylinders with compressed air in October 2022, in accordance with standard procedure. As he closed the valve on one of the cylinders, he heard a whistling noise and within seconds the cylinder exploded.

The man’s left leg was severed below the knee and he suffered severe injuries to his right foot, requiring emergency surgery. The Geelong property’s windows were blown out and it sustained structural damage.

Australian standards require scuba cylinders to be inspected and pressure-tested every 12 months. Those that have met requirements are subsequently referred to as “in test” and those not checked in the past 12 months are referred to as “out of test”.

A WorkSafe investigation found the cylinder that exploded was out of test, and it was not clear when it was last inspected. More than half of the 53 scuba cylinders in use at the workplace were out of test.

The court found it was reasonably practicable for the company to reduce the risk by ensuring cylinders that were out of test were separated from those in test.

“This is a horrific and preventable incident that has sadly left a worker with life-changing injuries,” WorkSafe executive director of health and safety Sam Jenkin said.

“It is particularly disturbing to see the failure in this case given diving is an industry where keeping equipment properly maintained and ensuring it complies with appropriate standards can be the difference between life and death.”