Reports of smoke in a Center City hotel forced hundreds of people outside in the dark around 4:30 a.m. Wednesday.
Guests stood outside the Sheraton Philadelphia Downtown Hotel at 201 N. 17th St. while firefighters investigated smoke coming from the building's basement, according to officials.
An ambulance transported two people to Hahnemann University Hospital, but it is unclear why.
Initial reports indicate an electrical problem may have caused the smoke.
Evacuations of the 757-room hotel, which sits next to Logan Square, took more than ninety minutes after fire crews arrived on the scene.
A Sheraton representative said it will be several hours before guests are allowed to return to their rooms.
The hotel is offering breakfast to those set to attend a 10 a.m. meeting at the hotel as part of the 69th Biennial National Association of Letter Carriers Convention.