Fires in aircraft freight holds caused by lithium batteries for consumer electronic equipment has been a growing worry for airlines, particularly in the last decade.
If the fire on board the Asiana Boeing 747-400 freighter on 28 July is confirmed to have been the cause of its fatal crash, it will be the second widebody freighter lost to fire in the last year, along with a UPS Boeing 747-400F lost near Dubai in September last year.
A list complied by the US Federal Aviation Administration of battery-related freight and baggage fires shows that the number of occurrences has increased dramatically over the last 20 years (see chart).
Among its freight payload, the Asiana 747 was carrying lithium batteries.
The subject of the increasing carriage of improperly identified and even banned dangerous goods in aircraft was top of the agenda at the World Cargo Symposium in March, according to the senior vice-president of AmSafe Industries, Ian Kentfield.
He said: "The rise in consumer internet trading has led to a massive increase in the transportation of high-tech equipment around the world, and it is often not appreciated that these goods can cause serious fires if not correctly categorised and protected for shipment".
Kentfield, whose company deals in cargo fire control products, talks of "a huge surge in the shipment of undeclared dangerous goods - from electronic products containing lithium batteries to mercury, gunpowder and even rocket engines.
"This phenomenon is the result of these products being sold on online auction and retail sites such as eBay, and then sent through the mail."
Logistics giant FedEx acknowledged the growing risk by installing cargo hold fire protection well beyond that required by law. This threat extends to passenger aircraft through freight and baggage carried in the cargo hold.
In 1996 a ValuJet McDonnell Douglas DC-9 was brought down in Florida by a belly hold fire caused by illegally packaged chemical oxygen generators, killing all 110 people on board.
The FAA list of battery-related onboard fires includes detail of carry-on electronic devices bursting into flames in overhead lockers, or in passenger bags in the freight hold.
Flightglobal's Ascend database describes 18 freight fire accidents since the early 1990s, of which five were fatal.
In almost every case the aircraft was written off, even if it landed before the fire rendered it uncontrollable.