This was in the news:
Lithium metal batteries deliver extremely high densities of energy, and if they are mishandled they can catch fire, a fire that can't be extinguished with halon, the most common kind of fire-suppression systems in passenger aircraft.
That's one reason the FAA banned shipments of nonrechargeable lithium metal batteries on passenger planes in 2004. But that ban only applies in the United States; international authorities are still considering whether to enact such a rule. Cargo and passenger aircraft are free to carry lithium ion batteries, although they are subject to labeling and packing regulations.
So what was on board Flight 370? Malaysian officials, after saying the cargo manifest would "be released in due course," later got a little more specific and said the Boeing 777 was carrying 440 pounds of lithium ion batteries. What else? Nothing that would cause a problem, the Malaysians assure us.
An Australian news media report said the Malaysian government refused to release the manifest to the Australian government, which would find such information helpful as it tries to map out a search.