"Naturally occurring radionuclides are widely distributed in the earth’s crust, so it’s no surprise that mineral and hydrocarbon extraction processes, conventional and unconventional alike, often produce some radioactive waste."

"Radioactive drilling waste is a form of TENORM (short for 'technologically enhanced naturally occurring radioactive material') — that is, naturally occurring radioactive material (NORM) that has been concentrated or otherwise made more available for human exposure through anthropogenic means. Both the rapidity and the extent of the U.S. natural gas drilling boom have brought heightened scrutiny to the issues of radioactive exposure and waste management."

Valerie J. Brown reports for Environmental Health Perspectives February 1, 2014. [2]