The fire started around 12:40 p.m. at a complex in the 400 block of High Road.
Bensalem Police tell Action News that the fire started in an apartment that was being worked on by maintenance.
"It was probably caused by paint thinner that dropped on the floor. There were contractors here working, and the fire was accidental," said Battalion Chief Robert Sponheimer.
Officials say a wet-vacuum was used to clean up the paint thinner. Heat from motor ignited the vapors which in turn caused the explosion and fire.
A total of six units were affected by the blaze, which left 10 people temporarily homeless.
"I'm a little upset with the timing of the holidays but no one got hurt and I didn't get it as bad as others," said George Kirby.
One firefighter was taken to the hospital with burns to the hands but no other injuries have been reported.
The families displaced are being assisted by the Red Cross. Anyone who would like to make a donation can visit: PhillyHomeFire.org.