Updated

A leading natural gas driller says it will disclose the precise chemicals it injects into a lucrative Appalachian reserve.

Range Resources Corp. wants to allay concerns over water contamination and defuse growing controversy about the industry's secrecy over the chemicals.

Officials at the Fort Worth, Texas-based company said late Tuesday they would post the information on the company's website and send it to regulators in Pennsylvania, where Range has permits to drill hundreds of wells into the Marcellus Shale formation.

The chemicals are mixed with water and sand and forced deep into the earth to break up shale and release natural gas.

Range says the amount of the chemical mix that federal regulators consider hazardous in a concentrated form is 0.04 percent of the total.