Team 800 responded at 0108 hrs to a cold storage and food distribution warehouse to assist first due companies comprised of equipment from 5 departments for an ammonia alarm going off. First in personnel made a quick assessment with the facility operations and activated emergency shut down procedures. The active leak was contained to the structural footprint and hazmat team members made entry to assess the conditions and source. 2 hazmat team entries were made with detection equipment to the ammonia operations room and the adjacent cold and dry storage areas to identify any IDLH atmospheres. High capacity ventilation, as a precaution, was provided by an additional mutual aid department air/foam unit. It was determined that facility operations could resume and the cold storage unit will be repaired by the facility's contracted service. Repair personnel were enroute immediately after reporting by the facility emergency operations manager.