The theory on the disappearance of Flight 370 that a serious fire raced through the fuselage incapacitating the pilots before they could send a distress call recieved a boost when the CEO of Malaysia Airline admitted that the plane carried highly flammable lithium-ion batteries as cargo.

Business Insider:

On Friday, Malaysia Airlines CEO released some new information that could bolster the fire theory. Four days after denying that the plane had carried any hazardous materials, the CEO admitted that it was carrying a shipment of lithium-ion batteries in its cargo hold.

These batteries, which commonly power cell phones and other gadgets, have occasionally caused fires, including on airplanes.  The Mail reports data from the FAA citing 140 incidents in the last 25 years involving lithium-ion batteries. At least two major crashes in the past two decades, meanwhile, have been caused by on-board fires, including a Swissair flight in 1998 and a UPS cargo plane in 2010.

Earlier this week, a former pilot named Chris Goodfellow articulated the fire theory, explaining how the plane's turn to the west could have been a standard attempt to head toward the nearest airport for an emergency landing. The plane's new heading put it on a course straight for Pulau Langkawi, a major airport in northern Malaysia.

Billie Vincent, a former Federal Aviation Administration security official, has also argued that the facts fit a fire. “The data released thus far most likely points to a problem with hazardous materials," Vincent told Air Traffic Management.net. "This scenario begins with the eruption of hazardous materials within the cargo hold – either improperly packaged or illegally shipped – or both.”

Malaysia Airlines says the batteries in the cargo hold were properly packed.

Vincent also suggests that the strange altitude readings that Malaysian investigators say they captured on radar—an ascent to 45,000 feet and then a descent to 25,000—could be explained by a fire. The pilots might not have been able to see the controls in the cockpit, Vincent said, and thus ascended higher than they intended. And, later, they might have been trying to get the plane to an altitude at which they could vent the plane and slow the progress of the fire, as well as prepare for an emergency landing.

Critics of the fire theory point out that no matter how quickly the fire progressed, the pilots almost certainly would have found an opportunity to send a call for help. Nor does it explain how the plane was able to maintain its structural integrity for 7 hours of flight - presumably with the pilots unconscious or dead.

The search for the possible debris spotted by the Australian satellite is continuing, in much better conditions. But the longer the search goes on without a clue about where the plane may have crashed or landed, the more likely it is that it will never be found.