WASHINGTON ― President-elect Donald Trump’s nominee to head the Environmental Protection Agency said at his confirmation hearing Wednesday that he didn’t know one of the most basic things about drinking water safety.

Sen. Ben Cardin (D-Md.) asked Scott Pruitt if “there is any safe level of lead that can be taken into the human body.”

The answer is a simple “no,” but somehow Pruitt didn’t say that.

“Senator, that is something I have not reviewed nor know about,” said Pruitt, the attorney general of Oklahoma.

“I would be very concerned about any level of lead going into the drinking water or obviously human consumption,” he continued, “but I’ve not looked at a scientific research on that.”

Pruitt shouldn’t need to look at the scientific research ― someone could just tell him. It’s not remotely controversial that lead, a deadly neurotoxin, can cause a host of health problems even in low doses. It can stunt children’s growth and permanently damage their young brains. Lead exposure has emerged as a plausible explanation for the rise and fall of violent crime in the 20th century.

One of the EPA’s jobs is to make sure that water utilities keep lead levels as low as possible. A key premise of the federal regulation that utilities have to follow, and which the EPA enforces, is that no amount of lead is safe.

Cardin asked his question in light of the Flint water crisis, which brought the dangers of water lead to widespread national attention at the end of 2015. The city of Flint had failed to follow federal lead rules, resulting in elevated lead amounts in the city’s drinking water ― and ultimately in blood samples taken from Flint children.

It was such a big story that even presidential candidates talked about it, including Hillary Clinton, Bernie Sanders, and yes, Trump.

“Someone nominated to lead the EPA should know, off the bat, that there’s no safe level of lead for human exposure ― a fact that’s hard to miss, frankly, after more than two years of news coverage about the city of Flint’s public health crisis,” Mae Wu, a senior attorney with the Natural Resources Defense Council, said in an email.

The EPA hesitated to take action in Flint even though the agency knew early on that the city and state had allowed excessive amounts of lead to leach into the city’s water from lead pipes that connect water mains to homes. The agency’s inspector general reported last year that the agency knew enough in June 2015 to declare an emergency; it didn’t declare one until the following January.

Pruitt gave a much more knowledgeable answer when Cardin asked about the EPA’s hesitation to step in sooner ― something Republicans have bashed the agency for despite their general antipathy toward aggressive regulation.

“If there’s an emergency situation, the EPA can enter an emergency order to address those kinds of concerns,” Pruitt said. “I think there should’ve been a more fast response, a more rapid response to Flint, Michigan.”