Billerica Rescue 1 is dispatched with a crew of two firefighters from Headquarters. The rescue serves as a technical rescue unit, mobile command post, fire scene rehab unit, lighting unit, and air supply unit. Rescue 1 contains equipment used during technical rescues such as vehicle extrication, structural collapse, water & ice rescue, and trench rescue. Hydraulic extrication tools, known as “The Jaws of Life”, can be found on this unit. The rescue also serves as a mobile air supply unit for the department. Because of the toxic atmosphere found in a burning building, firefighters wear air packs called self contained breathing apparatus (SCBA). Standard packs provide only 30 minutes of air, which during strenuous work, can be depleted in much less time. All fire apparatus carry spare bottles, but in multiple alarm fires or other lengthy incidents, the air can be used up quickly. A supplemental supply of breathing air is needed at these large incidents, which becomes the role of Rescue 1. The rescue is able to refill air bottles at the emergency scene allowing firefighters to safely return to work in the hazardous environment.