Kudos to the Kansas Corporation Commission for continuing to limit oil field wastewater injected underground in southern Kansas. The move is designed to further reduce the occurrence of earthquakes in the region.

Previous limits on wastewater injections have proved successful in reducing earthquakes.

As recently as 2012, Kansas had no recorded earthquakes. But in the fall of 2013, recorded earthquakes started becoming a monthly occurrence in southern Kansas as oil and gas production ramped up in the region. In 2014, there were more than 120 earthquakes in Kansas, including 31 in the month of November. Last year, the Kansas Geological Survey counted more than 160 earthquakes, including 56 that were magnitude 3.0 or greater.

The earthquakes began occurring after an increase in hydraulic fracturing, commonly referred to as frocking, which uses high-pressure liquid to fracture rock deep below the surface, freeing pockets of oil and gas. Fracking itself isn’t causing the earthquakes, the Kansas Geological Survey said. Rather, the practice of injecting wastewater — a byproduct of fracking — into rock formations underground was the most likely cause. The Associated Press reports that in Kansas the extraction of one barrel of oil produces 16 barrels of wastewater polluted with oil and salt. The preferred disposal method is deep-well injection.

Kansas isn’t the only state experiencing the problem — areas of Oklahoma near its border with Kansas now match northern California for the nation’s most earthquake-prone.

In March 2015, the Kansas Corporation Commission limited wastewater injection to 8,000 barrels per day in five areas in Harper and Sumner counties, the most quake-prone areas of the state. That move has had an impact, as seismic activity has slowed to fewer than 10 quakes per month in 2016. On Tuesday, the commission added a limit of 16,000 barrels per day in the rest of Harper and Sumner counties as well as parts of Kingman, Sedgwick and Butler counties. Violators of the disposal limit face fines of up to $10,000 per day, as well as a shutdown of the well.

Some commissioners wanted to go further with the limits. That ultimately may be necessary. In the meantime, it’s appropriate to continue tightening restrictions and measuring the results. Kansans should not be subjected to the risks associated with hundreds of manmade earthquakes per year.