The massive Sunrise propane explosion in 2008 was caused by an illegal "tank-to-tank transfer" along with a gas hose leak, the Toronto Star reports.

The cause was revealed in a confidential 367-page report by the Ontario Fire Marshal's Office obtained by the Star.

It says liquid propane was released from a hose after a "tank-to-tank transfer" was completed.

On Wednesday, the city councillor representing the ward containing the explosion site spoke out about the findings. Maria Augimeri says the report should be made public and similar operations shouldn't be near residential areas.

Augimeri says the provincial government should give municipalities the power to decide where propane facilites can be located.

The Star reports that Sunrise didn't have the right licence to perform those types of transfers, and it was previously barred from doing so by the Technical Standards and Safety Authority in November 2006. 

It's not know what actually sparked the blast that killed a Sunrise employee.