Someone called 911 to report an odor of gas just before 2 p.m.
Firefighters responded and discovered high carbon monoxide readings.
Officials said between 40 and 50 people were evacuated from buildings on Stratford Rd. in Prospect Park South.
MTA buses were called in to shelter the people who were evacuated.
No injuries were reported.
The Office of Emergency Management said the National Grid was on scene inspecting their infrastructure.
Elsewhere in the city, trucks were out salting side roads near the George Washington Bridge and other locations, and driving conditions were generally wet.
But the winter weather continued to cause trouble.
Video from the Citizen app shows flames shooting from a manhole at West 164th Street and Edgecomb Avenue in Washington Heights.