The European Parliament on Wednesday approved a proposal to regulate hydrogen cars, a move intended to prevent individual EU countries from adopting their own rules for the emerging technology.

The proposal, which still needs to be ratified by the European Union member states, lays out a general framework to regulate hydrogen cars for the first time. Among other provisions, it includes measures to help set up a European network of hydrogen fueling stations and to establish safety requirements for carmakers.

Specific measures to implement this proposal, including technical standards that automakers must follow, will be established later.

Although hydrogen cars are most likely to be decades away from being widely driven, the parliament has sought to begin regulating the sector in order to prevent individual European Union nations from creating potentially conflicting policies.

"There is a risk that every member state will draw up its own approval conditions, resulting in a distortion of a single market," according to the proposal. "This would lead to high costs for manufacturers, create safety risks and also considerably impede the spread of hydrogen technology in the EU."

The EU is setting out to regulate cars with combustion engines that burn hydrogen fuel as well as those that use fuel cells to run electric motors.

The proposal also defines "hydrogen vehicles" as those that run on both hydrogen alone and on a blend of hydrogen and natural gas. Concerns about natural-gas emissions prompted the parliament to label cars using the hydrogen-natural gas blend as a "transitional technology" leading to wider use of pure hydrogen cars in the future.

Although hydrogen cars can emit little to no pollution, the process of producing hydrogen fuels could undermine efforts to reduce pollution, the proposal noted.

In the United States today, 95 percent of hydrogen is made from natural gas and used to produce fertilizers or remove impurities such as sulphur from gasoline in industrial machineries, according to the National Hydrogen Association in Washington, D.C.

Major automakers have invested money in developing and road-testing hydrogen cars, but none has announced plans to introduce them to the mass market soon. A lack of hydrogen fueling stations is but one of the many formidable challenges to popularizing hydrogen cars. The hydrogen association lists 105 fueling stations in the United States on its Website.

A number of automakers are busy working on plug-in hybrid and all-electric cars for a mass-market launch in the next two years, which could be taking some of the focus away from hydrogen vehicles.

The hydrogen association teamed up with the U.S. Department of Energy and the California Fuel Cell Partnership last month to launch a two-week "Hydrogen Car Tour" from Maine to California.

The tour, aimed to raise the public awareness of hydrogen cars, featured cars from nine foreign and domestic makers, including Honda FCX Clarity, Toyota Highlander FCHV, and BMW Hydrogen 7.

When Arnold Schwarzenegger ran for California governor five years ago, he promised to support the development of a "hydrogen highway" with fueling stations throughout the state. Schwarzenegger has since signed legislation to attempt to make his idea a reality.  His goal was to create this hydrogen highway by 2010, but reaching that goal appears unlikely.

Last month, Honda announced that actress Jamie Lee Curtis took delivery of an FCX Clarity in Southern California. The automaker said Curtis was customer No. 2 on a list of 200 that plan to lease the model in the United States and Japan in the next three years (see Aptera Scores $24M to Produce Electric Ride and Green Brings Out the Experimental Side of Automakers).