Firefighter Joe Portner suffered a back injury after falling down some stairs, York City Fire/Rescue Services Chief David Michaels said. Portner was treated and released from York Hospital.
The fire, believed to have started in 268 W. Cottage Place, was contained to that building and the one next door. Both rowhouses are divided into apartments.
The cause of the fire is undetermined, Michaels said. Damage is estimated at $30,000.
The resident of the first floor apartment was at a neighbor's home while others were awaiting the arrival of the American Red Cross to assist them.
The fire was reported at about 11:36 a.
Keisha Godwin, who lives next door, said she and her husband, Darwin, were doing renovation work on the second floor of the apartment building, when they heard the smoke alarm. At first they though the resident of the apartment to the rear of the third floor had been smoking near the smoke detector, Godwin said.
But when they looked toward the rear of the building, she said, they saw the smoke and got out.
The third-floor-front apartment was recently renovated and not occupied, Godwin said.
Teresa Ann Boeckel contributed to this report.