Broadway was blocked by two New Haven Fire Department trucks for a half-hour Thursday evening.

Firefighters responded to the shops on Broadway at approximately 6 p.m. after a fire alarm went off. Responders from the NHFD could not immediately ascertain which store the alarm came from because the system is connected throughout the block, NHFD Lt. Gary Tinney said.

After approximately 30 minutes, firefighters determined that the alarm came from Urban Outfitters.

The store employees, who had closed the shop early at 6 p.m. for maintenance, set off the alarm while attempting to repair the heating system, Tinney said.