Transport and battery-manufacturing interests today called on governments worldwide to tighten enforcement on the air movements of lithium batteries, which are embedded in a growing number of products but which are prone to exploding if they are overheated due to overcharging or faulty manufacturing.

The protest took the form of a letter sent to unidentified battery-producing nations, according to the International Air Transportation Association (IATA), the leading global airline trade group and one of the signatory groups involved. The letter said governments must do a more consistent job of monitoring lithium-battery distribution at the origin point of the process, either with the manufacturer or with the distributor that is classified as the shipper, to determine whether product handling is in compliance.

The letter also called for "cooperative enforcement initiatives between jurisdictions" to prevent the lithium batteries being made in one country from being trucked across a border to be flown from another country, thus putting them out of control of the origin country's jurisdiction.

An industry source said the letter was aimed predominantly at China, which, along with Japan and South Korea, account for a large part of global lithium-ion battery production, according to an industry source. Though it is legal to ship the goods from China to Hong Kong, industry watchdogs have found that manufacturers that engage in the process have a higher incidence of flouting worldwide dangerous-goods transport regulations, such as failing to first test their batteries to meet United Nations testing requirements, improperly packaging, misdeclaring, or shipping counterfeit batteries. The manufacturers hope if they truck the goods to Hong Kong, the shipments can disappear within the massive volumes of cargo being air shipped daily from the island, thus avoiding the cost and obligations of compliance, the source said.

The source said the Chinese government is keenly aware of the issue and is doing what it can to inspect and, if necessary, intercept problematic battery shipments before they are trucked out of the country.

Commercialized in the early 1990s, lithium batteries are made of the world's lightest metal and hold a charge longer than metals of heavier density. They power most of the world's mobile devices and today power most electric cars. Lithium batteries remain expensive, though it is believed that as production capacity expands and processes improve, costs will drop dramatically, thus broadening the market for the product.

According to data from French company Avicenne Energy, global demand for lithium batteries from 2012 to 2020 will increase by 16 percent a year, compounded annually. By contrast, demand for traditional lead-acid batteries, which comprise the bulk of batteries being made today, will increase by just 4 percent a year.

However, lithium's properties can result in internal short-circuiting, which can cause overheating and a subsequent explosion. Some of the Boeing Co.'s 787 aircraft were grounded in 2013 because of fires caused by lithium-battery explosions. Earlier this year, the International Civil Aviation Organization (ICAO), an arm of the U.N., imposed a ban on lithium batteries being shipped in the bellies of passenger aircraft. The ban did not extend to all-cargo planes.

In the IATA statement, George A. Kerchner, executive director of the Portable Rechargeable Battery Association, which has been working with the airline group, said the inability of foreign governments to stop "rogue manufacturers" from disregarding international law is putting pressure on airlines and regulators to unilaterally ban all forms of lithium-battery shipments from aircraft. That, he said, would be a major mistake.

"A ban on the shipment of lithium-ion batteries aboard aircraft would put lives at risk by slowing delivery of life-critical and life-enhancing medical equipment, and jeopardize the security of many countries because a large number of military applications are powered by lithium batteries," said Kerchner.