The leak was first detected at about 11:00 p.m. at the Shaminy Brook apartments on the 2900 block of Knights Road in Bensalem.
Police and firefighters quickly evacuated the complex, while firefighters and PECO crews searched for the source of the leak.
There are no reports of injuries.
So far, there's no word on what progress crews are making in finding the leak, and no word on when the residents will be allowed back into the units.
