Moment drum launched into the air during Melbourne factory chemical explosion caught on camera [Video]

A 7NEWS reporter has captured the moment a drum was launched into the air during a massive factory fire in Melbourne’s west.

Fire crews spent about four hours battling a blaze at the ACB Group factory on Swann Dr, Derrimut.

WATCH THE VIDEO ABOVE: Exclusive footage captures drum flying from chemical fire.

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While filming the blaze, 7NEWS Melbourne reporter Paul Dowsley captured what appears to be a drum flying through the air in front of a plume of smoke.

A Fire Rescue Victoria (FRV) spokesperson confirmed one drum had landed on the Western Fwy, which has been closed to all traffic.

Dowsley also captured an explosion inside the factory, resulting in a ball of fire bursting into the air.

A Watch and Act has been downgraded to an Advice but businesses on Swann Dr and Bliss Ct will remain closed overnight.

FRV does not want people exposed to …