The U.S. Congress has ordered a study of potential alternatives because lawmakers are concerned about China's near monopoly and the fact that many of the mines are run by criminal gangs, The New York Times reported.
The elements, called rare earths, make magnets in electric motors lighter and increase the efficiency of light bulbs, among other things. Two of the elements, dysprosium and terbium, are in especially short supply because the demand for them is rising quickly worldwide.
Half the rare earth mines in China are regulated and the other half operate illegally, but even the legal mines often pollute water supplies and leave the land unusable, said Wang Caifeng, who regulates the rare-earths industry in China.
"In many places, the mining is abused," Caifeng told the Times.