According to a meaty Q&A on cnn.com, the CEO of Malaysia Airlines confirmed that the plane was carrying lithium-ion batteries. The significance, CNN reports:
Lithium-ion batteries are the type commonly used in laptops and cell phones, and have been known to explode, although it is a rare occurrence.
A fire attributed to lithium-ion batteries caused the fatal 2010 crash of a UPS cargo plane in Dubai. Lithium-ion batteries used to power components in Boeing 787 aircraft were also implicated in a series of fires affecting that plane.
So, in theory, a cargo of the batteries could have caused a fire that led Flight 370 to crash.
But Malaysia Airlines CEO Ahmad Jauhari Yahya told reporters the batteries were routine cargo.
“They are not declared dangerous goods,” he said, adding that they were “some small batteries, not big batteries.”