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A US university has stopped pursuing ‘cold-fusion’ patents based on the work of the chemists Stanley Pons and Martin Fleischmann. This represents “the end of a chapter” for the University of Utah, which has spent about $500,000 in pursuing the technology, according to Richard Koehn, its vice-president for research.

The decision comes nine years after a press conference at which Pons and Fleischmann described a simple technique for producing nuclear fusion at room temperature (see Nature 338, 364; 1989). “After nearly a decade of work on this subject by respectable people, there has been no progress in duplicating the original claims,” says Koehn. “For that reason, we decided it was not appropriate to spend any more public funds on this.”

The university had been bound by its original agreements with Pons and Fleischmann to fight for patent approval in both the United States and Europe. But such endorsement of the original claims has not been forthcoming. ENECO, the company in Salt Lake City that acquired rights to both the patents and technology, relinquished its licence last year after a fruitless and expensive attempt to win patent approval.

The university then tried to relicense the patents, but found no takers. Facing the estimated $1 million-$2 million in legal fees needed to pursue appeals in support of the patent applications, the university offered the licence to Pons and Fleischmann themselves, who declined. “At that point, we were finally free to step away from this technology,” says Koehn.

The episode has dealt a “body blow” to the university's reputation, he says, because of the lack of technical progress in cold fusion and the way the claims were originally publicized.

But cold fusion advocates are not giving up. “The abandonment of a patent has no bearing on the science,” Fleischmann said last month. “The research can proceed in a more positive way without a patent claim.”

Eugene Mallove, editor-in-chief and publisher of Infinite Energy magazine, admits: “There is very little money in this field, but hundreds of scientists are still conducting experiments. The real action these days is in the commercial sector.”

Government backing is scarce: the Japanese-sponsored research programme ended this year (see Nature 389, 10; 1997), and the US Department of Energy stopped funding cold fusion work in 1989.

Hal Fox, editor of the Journal of New Energy, thinks that cold fusion will ultimately be replaced by ‘plasma-injected transmutation’, a low-energy process that transforms heavy radioactive elements into stable ones.