Every scientist not on the corporate dole is upset about Scott Pruitt, Donald Trump’s pick to head the Environmental Protection Agency.

Like Betsy DeVos, who wants to destroy public education, and Jeff Sessions, who wants to destroy the Voting Rights Act, Pruitt is against the very laws he will soon be in charge of enforcing.

And the more you know about environmental law, the more you know that the Oklahoma attorney general and his minions could be way, way, way worse at the EPA than pundits and scientists have said. Yes, he’s a climate denier. Yes, he’s sued the EPA five times to prevent regulations (and lost every time). And yes, he has openly defied court orders on same-sex marriage and abortion, investigated the Humane Society for daring to back an animal welfare law, and opined that public schools should distribute religious materials to children. But he’s about to enjoy free rein to gut environmental regulations, without Congress or the courts to stop him.

That’s because environmental laws are deliberately broad, delegating massive authority to the EPA, which then has broad discretion to determine how to implement them. If you think about it, this makes sense. Congress isn’t populated by scientists but by politicians. So they set policy goals—clean air, clean water, toxin-free environments—and leave it up to the experts to determine how to meet them.

Most of the nuts and bolts of environmental law have thus been created not by Congress but by generations of EPA regulations and implementations. Clean air standards for factories, thresholds for pesticides in fuels or toxic chemicals in detergents and fuels, pollution levels for rivers—all of these, and many more, exist in regulations contained in the Code of Federal Regulations.

Usually, it’s conservatives who have complained about this. First, of course, they tend not to like anything that restricts unfettered capitalism, and environmental law certainly does that. Second, they tend not to like big government and unaccountable bureaucracy, and reams of agency-generated regulations are exactly that. And they tend to be wary of executive power in general.

Thus, for the last 40 years, corporations, industry groups, conservative think tanks, and Republican lawmakers have sued the bejeezus out of the EPA (and other agencies), challenging just about every regulation the agency puts out.

And usually, they have lost. Over several decades, the Supreme Court has tended to side more with the EPA than with its challengers. There have been exceptions—one of Justice Antonin Scalia’s last opinions required the EPA to limit mercury emissions only when it is cost-effective for corporations to do so. But in general, the court has observed that the “enabling statutes” passed by Congress deliberately cede authority to the EPA. Without congressional authority, the EPA couldn’t make up regulations and decide how to enforce them. But with it, the agency can.

Now the shoe is on the other foot. Now it’s arch-conservatives who will be controlling the EPA, with exactly the same level of authority as the environmentalists who preceded them.

And make no mistake: Pruitt’s nomination is historic. No one has ever headed the EPA with his level of anti-science, anti-environmental record, which includes multiple lawsuits against the EPA intended to prevent the EPA from doing its job. Which is now supposed to be his job. He is also a state attorney general with no experience managing an organization like the EPA (budget: $7.7 billion), no scientific background, and close ties to the very industries he is supposed to be regulating.

By way of comparison, George W. Bush’s EPA directors, Christine Todd Whitman, Mike Leavitt, and Stephen L. Johnson, were no dark greens, but they were reasonable figures. Whitman was an environmental moderate, Leavitt was a former governor who as EPA director pushed through good pollution restrictions, and Johnson was a scientist.

You’d have to go back to Anne Gorsuch, Reagan’s first EPA chief, to find an ideologue like Pruitt—and she was cited for contempt of Congress after failing to clean up Superfund sites, starving the EPA, and refusing to turn over critical documents to legislators. She ultimately resigned in disgrace.

So what are some examples of how Pruitt and his team could put this agency discretion into practice? Here, grouped into five categories, are 20 immediate steps they can take on their own, without congressional action, and with virtually no possibility of being stopped by the courts:

1. Cripple Enforcement. The main thing the EPA can do is simply fail to enforce all environmental laws by firing people and cutting enforcement budgets. This is what Gorsuch did in the ’80s: fire people, shrink the agency, and sabotage it entirely. Without adequate enforcement, no law—the Clean Air Act, Clean Water Act, whatever—has any meaning. This will likely happen immediately. In addition, the EPA can adopt new standards that lower the value of a human life (usually around $1 million) when being factored into cost-benefit analysis. That could prohibit regulation entirely if it costs companies more than a few thousand dollars in profits for each life saved. It will take a bit longer, but will happen in 2017.

2. Climate Change. Pruitt can decide not to regulate carbon dioxide emissions at all, derailing most climate change-prevention efforts in one quick stroke. Adopt junk science that defies the 100 percent scientific consensus (that is not an exaggeration; over a five-year period, 928 peer-reviewed articles endorsed climate change, zero opposed it) about climate change, putting EPA on record that it simply doesn’t exist. Concurrently, he can stop the EPA from collecting any data on climate change, ending the Greenhouse Gas Reporting Program immediately. Pull out of Intergovernmental Panel on Climate Change. Eliminate the “Social Cost of Carbon” metric. Hire frauds like Willie Soon to government positions. Prohibit the EPA itself from saying the words “climate change” or taking it into account at any time. (That has already happened in Florida.)

3. Air Pollution. Allow power plants to emit way more sulfur dioxide, causing acid rain (and increasing profits). Loosen the “NAAQS,” the National Ambient Air Quality Standards, to allow far more smog, carbon monoxide, and particulate matter into the air. Change automobile emission standards to allow dirtier cars and dirtier fuels. Loosen the “NESHAPs,” the National Emission Standards for Hazardous Air Pollutants, allowing asbestos to be reintroduced, factories to emit more air pollutants, etc.

4. Toxic Substances. Change standards for pesticides, raising amounts of pesticides deemed acceptable for agriculture, food, landscaping, etc. Lift ceilings on industrial pollutants, endangering workers but increasing profits. De-list Superfund sites and redirect Superfund money away from communities of color and others affected by environmental racism. De-list various chemicals from regulations under toxic substances control statutes.

5. Water Pollution. Publish new studies saying that fracking and mountaintop removal mining are perfectly safe and may be implemented anywhere in the country. Allow nuclear plants to release more radioactive material into rivers and ground water. Allow industrial and agricultural activities to release far more waste into water sources.

Chances are, unless you’re a huge environmental nerd, you haven’t even heard of most of these. (I ran the environmental law clinic at Yale Law School, and I worked for a former EPA deputy administrator.) And that’s the point. Big-ticket issues like climate change have grabbed the headlines, and they are important. But in terms of impact, the items on this list will be far more significant. And again, they will happen without congressional action, and with limited judicial oversight.

Don’t believe the hype about Scott Pruitt. He is far, far more dangerous than you think.