Victims of the Sunrise Propane blast in Toronto have the green light to press their collective lawsuit.

The court has certified the action against the company, some of its suppliers and the Technical Standards and Safety Authority.

Almost four years ago, the Sunrise distribution plant exploded in a fireball that killed an employee.

It also forced about 12,500 people from their nearby homes and caused about $25 million in damage to properties.

Lawyers say the crucial certification means victims are a significant step closer to settling their claims.

The class action seeks several hundred million dollars in damages.

Sunrise and two of its directors also face provincial-offences charges and could be fined millions of dollars if found guilty.

The government has said the blast occurred when propane vapour leaked from a defective hose or pump bypass and ignited during a risky truck-to-truck gas transfer.

Sunrise had been told almost two years earlier to stop the transfers but continued them as a matter of routine, according to court testimony.