President Donald Trump signed an executive order yesterday (February 28) directing EPA administrator Scott Pruitt and the Army for Civil Works to “review” the Clean Water Rule, also known as the Waters of the United States (WOTUS) rule.

The EPA and Army finalized the WOTUS rule in May 2015. It clearly defines what waters the Clean Water Act protects and, in turn, which drinking water sources. The Clean Water Act used to define protected waters as “navigable,” which was interpreted to mean ones that could fit a boat, reports NPR. But smaller streams and rivers eventually join larger rivers, so this regulation came about to protect them, too.

“President Trump’s reckless order is an assault on each and every one of us, our health and our well-being,” said Earthjustice President Trip Van Noppen in an online statement. “By attacking the Clean Water Rule and fundamental protections under the Clean Water Act, the president is putting the drinking water of 117 million people at risk, demonstrating that he puts the interests of corporate polluters above the public’s health.”

The way Trump sees it, however, this regulation impedes job creation—a common argument offered by his administration for eliminating climate regulation. During his signing of the order, Trump said, per his published statement:

The EPA’s so-called “Waters of the United States” rule is one of the worst examples of federal regulation, and it has truly run amok, and is one of the rules most strongly opposed by farmers, ranchers and agricultural workers all across our land. It’s prohibiting them from being allowed to do what they’re supposed to be doing. It’s been a disaster.

He went on to call it a “destructive and horrible rule” immediately before signing the executive order. Pruitt has already expressed his support, unsurprising given his criticisms as Oklahoma attorney general when the rule was first finalized in 2015. He was one those to sue the environmental agency over it in 2016 for the “significant and sovereign harm” the rule placed upon states. Pruitt joined one of the largest coal mining companies and 31 other attorney generals in a lawsuit, Murray Energy Corporation, et al. v. U.S. Environmental Protection Agency, et al.

This is a stark contrast to how former EPA administrator Gina McCarthy has responded publicly. Per Mother Jones reporter Rebecca Leber’s Twitter account:

Still, this executive order can go but so far, McCarthy claimed in her statement. “Only a new rule based on a new record can make current rules go away,” she wrote. “The only thing these orders do is make clear this Administration will defer needed public health protections for the American people for the sake of partisan politics.”

By this she means that repealing the Clean Water Rule would require a lengthy public process to redefine what waters are protected under the Clean Water Act. As Vox reported, this process includes “proposing a new rule that’s supported by extensive scientific and legal arguments, opening up the proposal for public comments, responding to those comments and then defending the final rule in court as  a superior approach.” It is a process which could take several years. 

(H/t NPR, Vox)