OKLAHOMA CITY (AP) — The Latest on efforts to reduce earthquakes in and near Oklahoma's oil and gas wells (all times local):
An environmental advocacy group is suing three Oklahoma energy companies, seeking an immediate drop in wastewater injection volume.
The Sierra Club filed the lawsuit Tuesday, the same day the Oklahoma Corporation Commission told well operators in northwestern Oklahoma to reduce disposal volumes. The group blames an increasing number of earthquakes on wastewater disposal from hydraulic fracturing operations at Chesapeake Operating, Devon Energy Production Co. and New Dominion.
Devon spokesman John Porretto says it would be inappropriate to discuss the litigation. The other companies didn't immediately reply to requests for comment.
The lawsuit was filed three days after the state's third-strongest temblor, a 5.1-magnitude earthquake in northwestern Oklahoma. People in 14 states reported feeling Saturday's quake — including some in Georgia, 900 miles away.
Oklahoma oil-and-gas regulators are making their most far-reaching directive yet in response to the spike in earthquakes in the state by asking the operators of nearly 250 injection wells to reduce the amount of wastewater they inject underground.
The Oklahoma Corporation Commission released a plan Tuesday that covers more than 5,200 square miles in northwest Oklahoma. It calls for a reduction of more than 500,000 barrels of wastewater daily, or about 40 percent less than previous levels.
The number of earthquakes with a magnitude 3.0 or greater has skyrocket in Oklahoma, from a few dozen in 2012 to more than 900 last year. Scientists have linked the quakes to the underground disposal of wastewater from oil-and-gas production.
A 5.1-magnitude quake hit the area Saturday, the third largest in state history.