The Massachusetts State Police Bomb Squad Monday afternoon conducted the safe detonation of fireworks previously confiscated by Haverhill Police. Deputy Police Chief Stephen J. Doherty Jr. told WHAV his department routinely collects old or confiscated fireworks and keeps them in a secure shipping container behind the police station at 40 Bailey Boulevard. As was the case Monday, the material was taken around 5 p.m. to the city’s Public Works lot at 500 Primrose St., where they were destroyed. The Haverhill Fire Department accompanied Haverhill Police to the site. A number of residents in the area and adjacent neighborhoods flocked to social media to report they heard the detonation.