A financially strapped Oklahoma oil company is defying the state regulator’s request that it shut down six wells used to dispose of wastewater, despite fears they may be contributing to earthquakes.

Sandridge Energy Inc., which has complied with similar requests in the past, said this time it won’t stop using its wastewater disposal wells, which are part of the company’s oil-and-gas fracking operations.

A growing body of research links temblors in Oklahoma and other oil-and-gas-producing states to the use of disposal wells, though Sandridge and other prominent shale producers have been vocal critics of those geologic reports.

The Oklahoma Corporation Commission, which regulates energy companies, is working on legal action to modify Sandridge’s permits in order to force it to comply, said Matt Skinner, a spokesman for the agency.

Oklahoma’s regulator has been clamping down on wastewater disposal, asking operators to voluntarily pull back on their use of disposal wells in earthquake-prone areas. Last year, those requests resulted in the shutting down or curtailing of operations of about 300 wells.