Multiple fire crews have battled large blazes at a petrol station and a factory in Sydney’s west overnight.

Dozens of workers self-evacuated from a plastics factory in Smithfield after a fire broke out just before 4am on Thursday.

Fire and Rescue NSW Superintendent Adam Dewberry told Sydney radio 2GB more than 100 firefighters and 25 fire trucks were sent to the fire, which took about an hour and a half to put out.

“Thank goodness for our firefighters who contained this fire to a quarter of the factory that could have been involved,” he said.

Crews remain on scene to ensure any fire remains are extinguished and determine how it started.

There were no reported injuries.

In the nearby suburb of Fairfield, investigators are examining the scene of a fire at a petrol station where multiple 200-kilogram LPG cylinders exploded.

About 6.30pm on Wednesday, crews arrived at the station to find a large, intense fire threatening to spread to nearby homes.

Residents rushed to safety as firefighters cooled the venting gas cylinders.

The blaze was brought under control after three hours, saving neighbouring homes and preventing flames spreading to the service station’s fuel tanks.

Fire investigation crews will work with police forensics officers on Thursday to determine the cause of the blaze.

– AAP