A UN committee will make the key decision on whether cartridges containing methanol pose a significant safety risk on commercial aircraft. Without approval, the commercial success of such fuel cells would be put under doubt.

The methanol fuel cells have been developed as an alternative to lithium ion batteries. They are smaller, cheaper and last longer. They could also be in production by next year, with a more advanced version expected to debut in 2006. But laws across the world threaten to undermine the technology.

Direct methanol fuel cells (DMFCs) mix methanol with air and water to produce electrical power. Models being developed for laptop computer use are capable of delivering enough power for between five and 20 hours, far outpacing current batteries and particularly useful for passengers on long-haul flights. However, at present passengers are forbidden to take cartridges containing methanol - which is flammable --on-board aircraft as a carry-on item.

The rule is one factor that caused NEC Corp to delay the commercialisation schedule of its first DMFC-powered laptop from this year to 2007.

The sub-committee of Experts on the Transport of Dangerous Goods, is due to meet between 29 November and 7 December in Geneva and decide on classification of methanol fuel cartridges as a category of dangerous goods that can be brought by passengers onto aircraft, said Jean Abouchaar, director, cargo regulatory & industry affairs of the International Air Transport Association (IATA)y.

If the committee agrees to the proposals, it will set in motion a series of required rule changes by the ICAO (International Civil Aviation Organization) and its member states that should see methanol cartridges allowed on aircraft from 1 January 2007. Otherwise, the process might be stalled for a further two years, he said. "The UN does not issue mandatory regulations, but its recommendation means that transportation authorities can go ahead," said Abouchaar.

The proposal to classify methanol has come mainly from the US Department of Transportation's Research and Special Programs Administration, he said.

The meeting could also help determine the fuel cell commercialisation plans of several of the world's largest electronics companies, including Fujitsu, Hitachi, Samsung and Toshiba all of which are developing direct methanol fuel cells (DMFCs).

In interviews, Toshiba and Hitachi have said that they think a mass market for DMFCs will emerge when PC users are able to carry methanol cartridges onto planes. "We don't think they [the IATA] are against methanol," said Toshiba spokeswoman Midori Suzuki. "It's just that it will take some time to go through the bureaucratic process."

Many companies have not adequately considered legal regulations and the time taken to implement changes, so they may well have fuel cells ready for the market before the laws are changed, said Atakan Ozbek, a fuel cell industry analyst with US-based technology research company ABI Research. "The issue stands a good chance of resolution as regulators appear to be aware of the urgency of the matter. Everyone realizes the importance of classifying it as soon as possible," Abouchaar said.

Grant Gross in Washington contributed to this story.