EPA Administrator Scott Pruitt has seemingly become to governmental ethics what Three Mile Island was to nuclear safety. A constant drumbeat of questions about his ethical behavior — excessive spending on security and office improvements, allegedly leveraging his personal position for his wife’s private gain, using EPA employees for personal work — has created a toxic political Superfund site within the administration of President Trump.

Neither Pruitt nor Trump, though, seems particularly concerned about it. Asked several months ago about the allegations Pruitt faces, Trump and his team said that they were looking into the issue, a bit of research that hasn’t resulted in any public acknowledgment of the questions that have been raised. The consensus is that any other president faced with a Cabinet-level official surrounded by a similar swarm of questions would have fired the official long ago, or that the official would have resigned. Tom Price, once Trump’s secretary of health and human services, resigned after only a small slice of similar alleged activity was revealed. Pruitt, though, is carrying on as though nothing had happened.

Even some of Trump’s allies are now calling for Pruitt to be booted. Fox News host Laura Ingraham, responding to The Post’s new report on Pruitt’s efforts to line up a job for his wife, called for Pruitt to go. A conservative nonprofit is running television ads making the same demand.

That Pruitt still has his job — and is still being praised by Trump — raises an obvious question: If the president doesn’t want to fire Pruitt and Pruitt won’t resign, is there any way to get Pruitt out of office?

We spoke by phone with Professor Kathleen Clark of Washington University Law in St. Louis to answer that question. Clark’s formal expertise overlaps with Pruitt’s interests: Government ethics.

There are, at the moment, at least 12 investigations into Pruitt’s actions, as tallied by the New York Times. Most are contained within the office of the EPA Inspector General. There are also investigations underway by the Government Accountability Office and the House Oversight Committee. The possible repercussions for Pruitt from those three types of investigation vary widely.

The inspector general is looking at violations of government ethics standards, among other things.

“For some of these government ethics standards or government regulations in particular,” Clark said, “the potential consequences for an actual violation would be employment-based discipline. That of course would depend on the president taking action against Pruitt.”

Pruitt being found to have violated the rules of his job, in other words, would mean that he would be reprimanded by his boss. His boss is Trump. And Trump could respond in any way he wanted: Firing Pruitt, demanding an apology, admonishing Pruitt — or he could do nothing.

We’ve seen, for example, several other members of Trump’s administration cited for violating the Hatch Act, which prohibits campaigning from a government position. None received so much as a slap on the wrist.

In the past, Clark said, officials found to have violated regulations offered their own apologies.

“Even where there was not formal discipline by the president, there was a kind of personal accountability through acknowledgment,” she said, referring to those past cases.

The Government Accountability Office is looking at Pruitt’s actions as a potential violation of the Antideficiency Act, which, among other things, bars spending more than has been appropriated. Violations of the act “in theory can be criminal,” Clark said, though she didn’t know whether any criminal charges had ever been filed against potential offenders. People had been found to have violated the act in the past, however — with punishment falling to their supervisors. Again: up to Trump.

Then there’s the House Oversight Committee, where things get interesting.

If the House generally wants to hold Pruitt to account, it has a lot more tools at its disposal than simply asking Trump to do something.

“Certainly the House and the Senate have the authority to investigate these alleged multiple violations, ethics and otherwise, at the EPA,” she said. “Of course, in the past, Congress has quite energetically investigated administration officials when it suited Congress’s political goals.”

That qualifier at the end is important. A Republican-led Congress is going to be less likely to hold a Republican president’s EPA administrator accountable than a Democrat-led one, though with midterm elections approaching and stories about Pruitt mounting, that calculus might shift.

So what can it do?

“They can call for testimony from multiple government agency officials. They can gather information and put that information out in reports, placing political pressure on the administration or a particular agency,” she said. “They can hold up confirmation of administration nominees. They can use their appropriations power to put pressure on an agency. They have multiple tools available to them — if they have the political will.”

Then there’s what Clark called the “nuclear bomb” of congressional actions: impeachment.

In 1876, Secretary of War William Belknap was impeached by the House, according to a 2015 Congressional Research Service report, the only Cabinet official to face that punishment. (You’ll remember that impeachment and removal from office are separate steps, the first decided by the House and the latter by the Senate, requiring a two-thirds vote.) Belknap resigned before the Senate could decide whether to boot him from the government, which it ultimately declined to do. Belknap’s misdeed? Misuse of the office for personal gain.

It’s also possible that Pruitt might eventually face (or might currently be facing) federal criminal investigation by the FBI. One possibility, Clark speculated, is that Pruitt’s use of EPA employees to do personal work on his behalf might constitute a theft of government services.

A former EPA official, John Beale, was convicted on similar charges in 2015, after spending years telling his colleagues that his frequent absences were a function of work he was doing for the CIA in Pakistan. They weren’t, and he was sentenced to 32 months in prison.

Pruitt is not known to be under investigation and the ways in which he is alleged to have misused EPA resources is a far cry from what Beale did. It’s possible, though, that for that or other violations Pruitt could face prosecution.

In which case it would again fall to Trump to do something about it. Trump could fire Pruitt — or he could allow him to serve despite a criminal conviction. He could also, of course, simply pardon Pruitt, since any crimes would have been federal ones. Once again, it’s largely up to Trump and Pruitt to decide if the administrator keeps his job.

“Pruitt does appear to be a serial offender,” Clark said at one point. “He actually seems to be a systematic offender.”

Unless he resigns or Trump wants to fire him, Pruitt can remain in his position despite any of the numerous investigations that surround him. Or he could make history as the first Cabinet-level official removed from his position by a Congress that had gotten its fill of news stories about his behavior.