Drilling companies have told us that extracting natural gas from the ground poses no threat to our drinking water.

But for the first time, a report from the Environmental Protection Agency (EPA) shows that may not be the case.

The report released on Dec. 8 shows that chemicals from “fracking,” the controversial process of withdrawing natural gas from the ground, have been found in a rural Wyoming aquifer. Fracking involves pumping water, sand and other chemicals into the ground to crack the shale rock that holds trapped gas inside.

“The presence of synthetic compounds such as glycol ethers … and the assortment of other organic components is explained as the result of direct mixing of hydraulic fracturing fluids with ground water in the Pavillion gas field,” the EPA wrote it its report.

The EPA first began investigating when in 2008 residents near Pavillion, Wyo., began complaining about bad smells and tastes in their water wells. The EPA responded by testing two wells in the Wyoming aquifer near where the natural gas drilling company Encana has drilled.

Studies found high levels of synthetic chemicals and methane and benzene levels that exceed the minimum standards of the Safe Drinking Water Act. The Department of Health and Human Services told residents to use alternative water sources for drinking and cooking and to vent away potential chemicals when showering.

Still, a spokesman for Encana told CNNMoney that the drilling company’s fracking process is likely not responsible because the test wells were far below the depth of regular drinking water wells.

Although the latest environmental concerns about the natural gas drilling is restricted to the Wyoming aquifer, it will fuel more debate in other areas of the nation where drilling for natural gas is prevalent. In the last decade, drilling has rapidly swept across 31 states including Texas, New York and Pennsylvania.

Gas well drilling has long been suspected to pollute the air with toxic chemicals and noise and has even been linked to causing earthquakes. Studies continue to determine whether those claims are accurate.

Nevertheless, “fracking” watchdogs have taken notice of the Wyoming report and are calling on politicians and drilling companies alike to improve the situation.