Next week, a committee of legislators will meet to debate the existence of a 21st century version of the Philosopher's Stone. What the alchemists of waste management claim to have created is not a process for turning base metal into gold but something almost as valuable: a way to turn the rubble of urban renewal into fuel to replace oil, natural gas or coal.

In 2003, New Hampshire had to find a way to dispose of 326,900 tons of construction debris, about half of it from out of state. One-third of it was put in landfills. The rest was run through Epping and Salem processing plants that sort the scrap and grind the wood into small pieces that can be burned like wood chips.

Presumably, although what emerges contains traces of paint and other materials, it is safe to burn in plants with the proper pollution control equipment. But even when "best available control technology," as it is known, is in place, some toxic emissions remain. Zero emissions is not an option. How much is safe - particularly for children living in the path of a plant's fallout - is a subject of debate.

Under existing New Hampshire law, processed construction debris cannot be sold as fuel. Almost all of it produced by New Hampshire facilities is burned by Maine power plants. But the Department of Environmental Services is studying a rule change that would allow debris that meets its standards to be certified as fuel.

The proposal raises many technical, environmental, social, political and emotional issues. The reclassified fuel could, for example, be burned in the controversial Bio Energy power plant in Hopkinton. That plant, whose permitting and legal problems have been chronicled in this paper, is an artifact of the area's industrial era. It has no place in a rapidly growing residential area. But it exists and must be dealt with.

Opponents see the plan to reclassify debris as an end run around the law. They believe it would allow the plant's owners to escape restrictions, including the prohibition that forbids a felon to hold an interest in a solid waste facility for five years after conviction. But the issue was destined to come up with or without the Bio Energy battle, and the ramifications of reclassifying waste extend far beyond Hopkinton.

Rising fuel prices have made certified waste more attractive as a fuel. Something must be done with the detritus of old buildings to rehabilitate them or build new ones. Burying wood that could be burned wastes energy and takes up scarce landfill space. Burning it under tight controls could lower electricity costs slightly and lessen dependence on fossil fuels. Those are arguments in favor of reclassifying debris.

But the change would come with its own set of problems. Reclassifying the waste will make it more attractive to open wood-to-energy power plants in New Hampshire, including a huge project proposed for Hinsdale and a small one in Barnstead. It will probably lead to the importation of more construction debris from other states.

Burning that waste means more air pollution in a state that already has one of the nation's highest asthma rates. It means more ash to bury, some of it heavily laden with toxins, and more truck traffic on the state's roads.

Lawmakers enacted a moratorium on the burning of solid waste that expires next July 1. Certifying construction debris as fuel would circumvent that moratorium. But there's no rush. The supply of debris is inexhaustible.

The Department of Environmental Services should continue its work testing fuels and analyzing potential health effects. But it should wait for the legislative committee to issue its report before deciding whether to reclassify waste.

It makes no sense to enact a rule that might in short order be trumped by an act of the Legislature.