The government should issue more stringent rules for how rechargeable batteries are shipped on planes to prevent uncontrollable fires, the chairman of a federal accident investigations board said Tuesday.

Lithium-ion batteries should be separated from other flammable cargo and the amount of batteries in a single cargo pallet or container should be limited, Chris Hart, chairman of the National Transportation Safety Board, said in a letter to the government agency that sets rules for transporting hazardous materials.

Rechargeable batteries, which are widely used in consumer electronics like cellphones and laptops as well as some cars, can short-circuit and ignite for a variety of reasons, including when they are damaged, contain defects, are packaged incorrectly, or exposed to extreme temperatures.

The recommendation is based on an investigation by South Korean authorities of the destruction of an Asiana Airlines cargo plane in July 2011, Hart said. A fire on board the plane developed on or near two pallets situated close together, one containing lithium-ion batteries for hybrid-electric cars and the other flammable liquids used in the production of television screens.

Although it couldn’t be determined what ignited the fire, the board is concerned that in the event of an in-flight fire the close proximity of rechargeable batteries to other flammable cargo would increase the severity of the fire and reduce the time the flight crew has to respond, Hart told the Pipeline and Hazardous Materials Safety Administration.

Rechargeable battery fires can burn as hot as 1100 degrees. That’s the melting point of aluminum, which is typically used in aircraft construction.

Seventeen minutes after the Asiana pilots reported the fire, their Boeing 747 broke up over the South China Sea despite desperate efforts to reach a place to land. Both pilots were killed.

At the behest of the battery and consumer electronics industry, Congress passed a law in 2012 prohibiting the government from issuing regulations regarding the shipment of lithium batteries that are more stringent than standards issued by the International Civil Aviation Organization, a U.N. panel.

However, NTSB said that PHMSA can issue regulations requiring the separation of rechargeable batteries for other flammable cargo because the 2012 law makes an exception for cases where there is “credible evidence of a deficiency in the international regulations that has substantially contributed to the start or spread of an on-board fire.”

Separately, the Federal Aviation Administration issued a safety alert Tuesday to U.S. and international air carriers urging them to conduct assessments of the risks of carrying cargo shipments of rechargeable batteries in the bellies of passenger planes.

(AP)