[1] Hundreds of thousands of gallons of water carrying radioactive waste from rare earth element mining spilled into and around Ivanpah Lake.

[2] In the 1980s, the Mountain Pass rare earth mine began piping wastewater as far as 14 miles to evaporation ponds on or near Ivanpah Dry Lake, east of Interstate 15 near Nevada.

The scale is radioactive because of the presence of thorium and radium, which occur naturally in the rare earth ore. A federal investigation later found that some 60 spills—some unreported—occurred between 1984 and 1998, when the pipeline was shut down.

In all, about 600,000 US gallons (2,300,000 L; 500,000 imp gal) of radiological and other hazardous waste flowed onto the desert floor, according to federal authorities.

After preparing a cleanup plan and completing an extensive environmental study, Unocal in 2004 won approval of a county permit that allowed the mine to operate for another 30 years.