A large gas leak that engulfed vehicles and people at a gas station in Taranaki could have had deadly consequence for the six workers on site at the time, WorkSafe says.

An investigation by the workplace watchdog showed the November 2016 incident in New Plymouth saw 140 litres of liquid petroleum gas discharged from a trailer-mounted calibrating unit because of poor practice.

"One worker was taken to hospital after receiving cold burns to the leg and another person suffered a knock to the head after the leak engulfed all the personnel and vehicles present at the vehicle loading bay site."

A WorkSafe investigation found the companies; First Gas Limited, Gas Services NZ Limited and Beach Energy Resources NZ (Kupe) Limited had breached health and safety legislation.


First Gas Limited was fined $188,250, Beach Energy Resources NZ (Kupe) Limited was fined $215,625 and Gas Services NZ Limited was fined $215,625.

Reparations of $13,500 were awarded to one victim, and $3500 to another

Their investigation found there were shortcomings including failure to adequately secure a valve on the calibrating unit.

None of the companies involved had managed the health and safety of their own or other workers on site that day, WorkSafe said.

Energy and Public Safety head of high hazards Tony Hetherington said there was a "high potential for death or serious harm if ignition occurred".

"This was an incident that had the potential for loss of life and serious injury. If the gas had ignited there would have also been significant damage to the plant and equipment at the site.

"These failings were concerning from a health and safety viewpoint, but also illustrate how good safety management safeguards the ability of the business to maintain operations."

The companies should have sufficient systems in place to prevent such an incident, especially with the potential "for a major incident" with a flammable substance.