The first service to attend were a Patient Transport Ambulance crew who took the decision to divert straight to the scene because they were so close at the time of the explosion. This initial crew saved dozens of lives by taking control of the evacuation and pulling the injured to safety. Around a dozen were trapped in the rubble. Fire crews used specialist search-and-rescue equipment, including sniffer dogs, carbon dioxide detectors (which detect the respired carbon dioxide of trapped persons), thermal-imaging equipment, and fibre-optic cameras to search for people trapped in the collapsed building. Some trapped workers were able to make themselves heard by shouting, or by using their mobile phones. Fire and Ambulance crews pulled seven people alive from the rubble on 11 May. The search through the factory's ruins continued for the following three days.