Rescue crews raced to assist a worker who was left partially buried in a trench collapse in Haverhill on Wednesday morning, officials said. The worker was at a dig site in the area of Carleton Street and Peoples Place when the trench collapsed around 10 a.m., leaving a man buried up to his chest, according to the Haverhill Fire Department. Firefighters managed to pull the worker out of the trench without any problems. He was not injured. There were no additional details immediately available. An investigation remains ongoing.