On 15 December 2006, a Boeing 737-800, being operated by Continental Airlines on a scheduled passenger flight made an emergency en route diversion to Colorado Springs, Colorado, after the cabin crew reported an in-flight fire. The flight had originated at Houston Texas and was en route to Portland, Oregon. Night Visual Meteorological Conditions (VMC) prevailed at the time of the event.
The fire was started after a personal air purifier device, used by a passenger during the flight, exploded. The airplane sustained minor damage. One passenger received a minor burn injury. Six persons were transported to a local hospital. They were treated for smoke inhalation and released.
The device that initiated the fire was sent to National Transportation Safety Board (USA) (NTSB) for analysis.
The device, “According to a sales brochure, it "generates an intense electrostatic ion wind that charges floating particles in the 'breathing zone.' The particles are substantially repelled away from the wearer, creating an almost particle-free 'exclusion zone' for toxic allergens, smoke, dust, viruses, and bacteria. Perfumes and odours can also be minimized by the ion particle-charging-effect."
The Fire and Explosion Specialist's report included the following information:
"The unit originally came with a 3.6V CR123A size non-rechargeable lithium primary battery. A kit containing a charger and a rechargeable lithium-ion battery was also available for this unit."
Further on, the report included data from EDS analysis of the splatter that was found on the device. It showed the presence of manganese - manganese dioxide is a component of primary (non-rechargeable) lithium batteries.
“The specialist's report noted that in testimony given at NTSB public hearings on the hazards associated with primary and secondary lithium batteries, a short circuit was "the most common cause of battery fires. The short circuit can be caused either by design flaws, manufacturing defects or improper packaging and handling. Charging non-rechargeable batteries can result in an internal short that can lead to thermal runaway and battery failure. Batteries are generally not designed to be able to contain catastrophic failures, and when they go into thermal runaway they often explode and expel their contents to the environment potentially causing ignition in areas well beyond the initiating battery cell
“The National Transportation Safety Board determines the probable cause(s) of this incident as follows. A short circuit in the primary (non-rechargeable) battery, most likely due to it being recharged. This internal short led to thermal runaway, battery failure, and an explosion.”