Construction will resume Thursday at the site where a New York City subway worker got stuck in mud for nearly four hours before being rescued.

A spokesman for the Metropolitan Transit Authority said workers must wear harnesses. Areas without any support underneath will be marked off with cones near the site of the accident.

Fire officials said the worker was pulled out shortly after 12:30 a.m. Wednesday, about four hours after he became stuck in the tunnel 75-feet below ground.

Authorities said he was treated for hypothermia and was in serious but stable condition at a hospital.

More than 150 firefighters responded to help rescue the worker at the construction site of the Second Avenue subway on Manhattan's Upper East Side.