The Bush administration has been busily touting fuel-cell cars as a critical component of its energy plan and the solution to many an environmental woe. But what if the solution turns out to cause its own problems? According to new research published in this week’s issue of Science, the technology used in hydrogen fuel cells could contribute to the destruction of the ozone layer, which protects the Earth from excessive doses of ultraviolet light. If fuel cells were used to power everything from cars to utilities, the researchers found, large amounts of hydrogen would drift into the stratosphere and increase the depletion of the ozone layer. The technology could be refined to mitigate the problem, but the scientists emphasized that the likely impact on the ozone layer must be taken into account when planning the shift to a hydrogen-based economy.