CFA crews from Silvan, Mount Evelyn and Wandin were called to a shed fire in Silvan at 6.18am on 2 April.
The fire was in a farming property’s shed on Lewis Road which contained appliances and agricultural chemicals inside.
Silvan CFA captain Shane Peacock said crews were called in after local residents heard loud explosions.
He said two trucks from Silvan, one truck each from Mount Evelyn and Wandin and Bayswater’s specialist Breathing Apparatus Unit were needed to contain the blaze.
“We were called out to a shed fire that was going with explosions heard in Lewis Road,” Mr Peacock said.
“When we arrived the shed was fully involved, it was well and truly alight.
“It was suspicious in nature so police were called and are currently investigating.”
Mr Peacock said despite the blaze being suspicious, chemicals and fertilisers should always be correctly stored safely within sheds.
“I’m not saying that was the direct cause or made it worse but we want to make sure any chemicals and flammable materials are correctly stored inside farm sheds,” he said.
There were no reports of any injuries during the incident.