The fire was reported around 11:30 a.m. Thursday at Monroe Energy on the 4100 block of Post Road.
Company officials say the fire started in a process unit pump room.
Video from Chopper 6 showed fire crews dousing the blaze from multiple angles.
A large column of black smoke could be seen rising into the air.
Chopper 6 video of refinery fire in Trainer, Delaware County
The Trainer Borough Police Department said the air quality is at a "nuisance" level, and it is recommended that people within a half mile of the refinery shelter in place.
Monroe Energy said in a statement that its own air monitoring results show no risks to the community at this time.
The cause of the fire is not yet known.
Stay with Action News and 6abc.com as this story develops.