THE BRONX - Officials say a rooftop caught fire Monday partly because of the extreme heat. 

The incident happened on the roof of the Montefiore North Wakefield Campus on Carpenter Avenue and the corner of E. 231 Street. According to officials, a generator being tested caused some of the roof materials to catch on fire. They say they evacuated patients and staff from the top two floors of the hospital. 

Officials say the fire was a multi-alarm fire because of Monday's high temperatures. They say there were only two minor injuries to firefighters.

Patients were allowed to returned to the hospital while repairs were being made to the roof. Con Ed also came to the scene to check gas lines, which it says are fine.