Major news for frack-followers: A Duke University study published this week finds homeowners living near fracking wells may be at an elevated risk of drinking water contamination.

The study, performed by researchers at Duke’s Nicholas School of the Environment, analyzed 141 drinking water samples from water wells in northeastern Pennsylvania, prime fracking country.

According to the study, methane concentrations were six times higher and ethane concentrations were 23 times higher at homes within a kilometer of shale gas operations. Propane was found in 10 samples, all of them within a kilometer of fracking sites.

Robert Jackson, a study co-author and Nicholas School professor, suggested in a school statement that “poor well construction” may be to blame for the contamination.

“Distance to gas wells was, by far, the most significant factor influencing gases in the drinking water we sampled,” Jackson said.

While a previous Nicholas School study has found methane contamination near fracking wells, the new study is the first to link drilling with ethane and propane contamination, according to the statement.

All three gases are considered to be flammable with a risk of explosions. Methane is generally thought to be non-toxic, although propane and ethane can pose health risks, such as asphyxiation, in high concentrations.

The study is released as North Carolina lawmakers continue to debate the contents of Senate Bill 76, a bill that may ultimately authorize the N.C. Department of Environment and Natural Resources to begin issuing fracking permits in March 2015.