Anyone who has ever carried a battery and spare change in the same pocket knows that things can heat up considerably when that battery gets going. Never done that? How about crossing up and connecting together two nine-volt batteries? That neither? Well, trust me, it gets hot.

The Associated Press reports that something quite like that happened aboard a UPS plane in Dubai three years ago. In that case, a fire started that raged quickly through the whole plane, until finally the plane crashed in the desert.

Suspicions about the fire starting from batteries had been bandies about before. Every single 787 plane was grounded earlier this year after a fire in a battery on a 787 parked at Logan International Airport. Another smoking battery caused an emergency landing by an All Nippon Airways 787 in Japan.

But this battery fire was not in the batteries that help power and run the plane. The fire on the UPS plane began in cargo, where a load of batteries was being transported.

A recent report by the General Civil Aviation Authority in the United Arab Emirates found that “with reasonable certainty” the fire began in cargo where “thousands” of lithium batteries of different types were being held for transport. The report could not be completely sure, but they did note an event called a “thermal runaway”, which is when a battery starts to heat up because pole connections are crossed – much like hooking two 9-volt batteries together. That reaction, it is thought, caused that battery to heat to a critical point, catching fire, which then heated the nearby batteries, then resulting in their explosions. Finally a fire raged through the plane.

“The fire escalated rapidly into a catastrophic, uncontained” blaze, the report said.

The director of the Air Line Pilots Association’s dangerous goods program, Mark Rogers, said the UPS plane was carrying between 80,000 to 90,000 lithium ion and lithium metal batteries as cargo and in equipment.