DENVER (AP) -- The energy company that found loose hydrocarbons near Parachute Creek in western Colorado says the leak was due to a failed pressure gauge on a pipeline.
State officials said Wednesday they're still investigating.
Hydrocarbons, including the carcinogen benzene, were discovered in soil and groundwater near the Williams natural gas processing plant in Parachute in early March.
Williams said Wednesday that a pressure gauge failed in December, and a leak started Dec. 20. It was stopped Jan. 3.
At that time, crews were unaware just how much had seeped out.
The contamination was rediscovered in March when workers excavated the area.
Williams now estimates more than 10,000 gallons of natural gas liquids leaked from the pressure gauge. About 6,000 gallons have been recovered.
Williams says the contamination hasn't reached Parachute Creek.