The blaze on the 1200 block of Baker Street broke out just after 12 a.m. Sunday, Oct. 9, according to the Chester Bureau of Fire.
Two houses were up in flames by the time crews arrived.
One of the firefighters became trapped when they partially fell through the first floor, fire officials said. That firefighter was freed by crew members within minutes.
Overall, a total of three firefighters were taken to Crozer Chester Medical Center, where they were listed in stable condition, authorities said.
The fire was placed under control about two hours later.
The cause and origin remain under investigation by the Chester Bureau of Fire Marshall's office, Chester Police Crime Scene Unit, Delaware County Criminal Investigation Division, and Pennsylvania State Police.
Click here to follow Daily Voice West Chester and receive free news updates.