THE cause of a potentially fatal gas explosion at Morty's BP Service Station in Launceston is under investigation by Workplace Standards Tasmania.
The explosion, which occurred during daylight trading hours on November 27 last year, blew the gas pit's metal seal several metres into the air.
It is believed that a damaged or faulty light within the chamber arced, triggering the combustion.
Workplace Standards general manager Roy Ormerod said workers had been conducting maintenance on the site about the time that the explosion occurred.
"The big risk in these sorts of issues is that if someone was in the pit at the time that it happened, it could be fairly dangerous - essentially fatal," Mr Ormerod said.
"We're still looking at why is it that the fitting that the globe was encased in had been cracked, and how that managed to avoid visual inspection at the time.
"It's one of those things you just don't allow to happen."
Workplace Standards is interviewing BP and its gas supplier Gilbarco in relation to the incident, and is investigating whether there was a breach of the workplace safety act.
A BP spokesman said: "BP treats any loss of containment very seriously, and an investigation into the cause is under way. BP is co-operating fully with the regulator."
Mr Ormerod expected a decision about prosecution to be made within the next few months.
"It's (an explosion of this nature) a first for us," he said.
"We have a 12-month window in which we must initiate any action ... we usually want to action these things within six months."