HOUSTON (Reuters) - Federal regulators have concluded that recent earthquakes in North Texas are likely linked to wastewater disposal wells used by the oil and gas industry, echoing findings from researchers at Texas universities.
EPA officials made the comment in a letter to the Texas Railroad Commission, which regulates the oil industry in the top crude-producing state.
Quakes have been tied to the injection of saltwater, a normal byproduct of oil and gas drilling, into deep disposal wells and underground caverns.
The Railroad Commission, which was not immediately available for comment, has in the past questioned the causal link found in university studies. But Texas has moved to install more earthquake monitoring stations.
"EPA believes there is a significant possibility that North Texas earthquake activity is associated with disposal wells," said the Aug. 15 letter reported by the Texas Tribune on Tuesday.
The EPA said it was concerned about seismic activity in the Dallas-Fort Worth area because of its potential to affect underground sources of drinking water.
Regulators in Oklahoma have ordered dozens of disposal wells to be shut in to curb a spate of quakes in that state.
The use of disposal wells intensified during the fracking boom, although U.S. oil and gas drilling has slowed recently on the worst price crash in years.
(Reporting by Terry Wade; Editing by Peter Cooney)