A report from the U.S. House of Representatives said oil and gas companies involved in shale gas production used fluids containing dozens of chemicals that are carcinogenic, considered harmful in drinking water or are listed as hazardous under the Clean Air Act.
"And some were extremely toxic, such as benzene and lead," the report said.
The report said that from 2005-09 energy companies injected more than 750 million gallons of fluid into shale formations to extract natural gas.
DeGette claims in the report that more than 1.5 million gallons of carcinogens were injected into shale formations in Colorado during the study period.
The House report comes on the heels of a Cornell University study published online in the journal Climatic Change that concludes methane leaked during shale gas production does more harm to the environment than burning coal.
The U.S. Energy Information Agency said shale gas production will make up about half of the total natural gas production in the United States in the next 25 years.