In 1989, two chemists at the University of Utah announced they had produced nuclear fusion in a jar at room temperature.
The claim collapsed within months when other laboratories could not reproduce it, and cold fusion became a byword for a result that did not survive scrutiny.
Two United States Department of Energy reviews, in 1989 and 2004, found no convincing evidence that nuclear reactions were taking place.
However, the field did not disappear entirely.
A small research community has continued to publish on what is now usually called low-energy nuclear reactions, or LENR, and a handful of funding agencies have supported exploratory work.
