NTSB: Plane batteries not necessarily unsafe

(AP) The nation's top accident investigator says lithium ion batteries like the ones that caused a fire in one Boeing 787 Dreamliner and smoke in another aren't necessarily unsafe for use in aviation, but safeguards are needed.

National Transportation Safety Board Chairman Deborah Hersman says she doesn't want to categorically rule out the use of lithium ion batteries to power aircraft systems, but that manufacturers need to build in safeguards that protect against battery fires.

Hersman told reporters Wednesday the board is still weeks away from determining the cause of the Jan. 7 battery fire in a Japan Airlines 787 while it was parked in Boston.

She also said the board is looking into whether the batteries should have to meet tougher testing standards adopted after regulators certified the 787s batteries.