Several apartments in Sunset Park had to be evacuated because of carbon monoxide Friday. Firefighters responded to the gas leak just before 9 a.m. The FDNY tells News 12 the gas leak started in the basement of a business and spread to two other buildings. There are businesses on the first floor as well as apartments in the top two floors. Officials say 30 people were evacuated and it took National Grid crews about an hour to locate the leak and shut off the valve. Everyone who was inside the building at the time was reported safe and has since been let back in. Officials are investigating the exact cause of the leak.