The state of California sued the Trump administration in federal court on Wednesday for repealing the Obama administration’s 2015 fracking rule regulating oil and natural gas drilling on federal lands.

“Once again, President Trump and Interior Secretary [Ryan] Zinke didn’t let the law or facts get in their way in their zeal to repeal the 2015 Fracking Rule,” said Attorney General Xavier Becerra, in announcing the lawsuit, filed in the U.S. District Court for the Northern District of California. “The Interior Department’s own factual record shows that the risks to our health and environment are real. So, once again, the California Department of Justice will get in the way of another reckless Trump violation of our laws.”

The Obama-era rule targets the practice of hydraulic fracturing, or fracking, which has made the U.S. the world’s leading producer of natural gas. The rule is intended to increase the safety of fracking by reducing the risk of water contamination. It would have forced companies to comply with federal safety standards in the construction of fracking wells and to disclose which chemicals they used in the fracking process.

California argues repealing the rule ignores environmental risks, and is “devoid of any reasoned analysis,” violating the Administrative Procedure Act, federal land management statutes, and the National Environmental Policy Act.

Killing the rule has been a top priority of the oil and natural gas industry, as well as Republican lawmakers from Western states.

The rule affects oil wells on public lands that are found mainly in the West.

The rule never took effect, due to legal challenges.