By Laura Barron-Lopez - 07/01/14 09:32 AM EDT
New and unconventional wells leak more often than older and traditional ones in Pennsylvania's gas boom, according to a new study.
The study, which consists of state inspection reports for 41,000 wells, states methane leaks could be a growing problem for natural gas drilling across the U.S., The Associated Press reports.
The report, funded by an environmental activist group, found older wells, which were drilled before 2009, had a leak rate of 1 percent.
With unconventional wells built before and after 2009, however, the leak rate reached nearly 10 percent in the northeastern part of Pennsylvania.
Unconventional wells are those drilled horizontally and are dubbed fracking.
Newer traditional wells, which are drilled straight down, leak at a rate of roughly 2 percent, AP reports.
A spokesman for the Marcellus Shale Coalition, Travis Windle, slammed the study, stating it indicates the green group's "clear pattern of playing fast and loose with facts."
Regulatory officials in the state said records of gas wells show that the number of leaks are on the decline from 2010 levels.