Oil and gas companies operating in Colorado are among many that say they will voluntarily disclose the chemicals used in hydraulic fracturing.
The technique — also known as "fracking" — that blasts water, sand and chemicals into rock layers deep underground to unlock oil and gas.
The companies are uploading data, including well locations, this week to a website created by the Groundwater Protection Council, a national association of groundwater protection agencies, and the Interstate Oil and Gas Compact Commission, an interstate commission created in 1935. Both are located in Oklahoma City.
