A possible carbon monoxide leak in Northeast Philadelphia sent four people to the hospital Monday morning.
Investigators evacuated two homes on the 2000-block of Lansing Street in the city's Rhawnhurt section around 5 a.m.
Carbon monoxide poisoning symptoms sent four residents of one of the homes to a nearby hospital.
The house next door was evacuated as a precaution.
Police are using fans to air out the homes. PGW is on the scene.
This story is developing. Check back with NBC10.com for more details.