A worker has died after a chemical explosion caused a factory fire in Melbourne’s west.

It took fire crews more than two hours to bring the blaze under control following the explosion at the factory in Derrimut about 9.45am on Thursday.

About 80 firefighters battled a chemical fire in a warehouse at the back of the property and at least 30 people at the factory were forced to evacuate.

Police discovered a dead worker, a 44-year-old man from Hoppers Crossing, inside the building.

Nobody else was injured in the explosion.

Police said the circumstances surrounding the incident were yet to be determined and the investigation was ongoing.

A Fire Rescue Victoria scientific officer was at the factory to provide specialist chemical advice.

WorkSafe was also investigating the fire, a spokeswoman said.

Police urged anyone with information about the fire to contact Crime Stoppers.

– AAP