For fires not suppressed by initial attempts or those in which evacuation may be hindered by the location or intensity of the fire, the use of a por-table fire extinguisher is warranted. A CO2 extin-guisher should be safe during external and internal exposure for fires on the patient in the operating room. CO2 readily dissipates, is not toxic, and as used in an actual fire is not likely to result in thermal injury. FE-36, manufactured by DuPont, also can be used to extinguish fires but is expen-sive. Both choices are equally effective and accept-able agents as reflected by manufacturers’ product information.
“A”-rated extinguishers contain water, which makes their use in the operating room problem-atic because of the presence of so much electrical equipment. A water mist “AC”-rated extinguisher is excellent but requires time and an adequate volume of mist over multiple attempts to extinguish the fire. Furthermore, these devices are large and dif-ficult to maneuver. Both can be made cheaply in a nonferromagnetic extinguisher, making them the best choice for fires involving magnetic resonance imagers. Halon extinguishers, although very effec-tive, are being phased out because of concerns about depletion of the ozone layer, as well as the hypoxic atmosphere that results for rescuers. Halotrons are “greener” halon-type extinguishers that may have fewer effects on the ozone layer.