A final report of a major federal study found no evidence that hydraulic fracturing caused the contamination of drinking water in Pennsylvania.
The Energy Department report said no traces of chemicals or brine water used during the drilling process for natural gas were found in drinking water, The Associated Press reports.
{mosads}The report is the first time a company agreed to have an independent monitoring of its fracking operations. The study lasted for 18 months.
After tracking operations 18 months after the fracking process, researchers said the chemicals used to break up rock and release deposits of natural gas remained roughly 5,000 feet below drinking water supplies.
Still, the Energy Department noted that oil and gas drilling at other sites across the U.S. could have different results due to difference in geology or drilling methods.
Another recent study by five universities, including Duke and Stanford, found that faulty gas wells were to blame for contaminating drinking water supplies in Pennsylvania and Texas.