About four decades ago, when the U.S. Environmental Protection Agency (EPA) was first trying to figure out what to do about lead in drinking water, Ronnie Levin quantified its damage: Roughly 40 million people drank water with dangerous levels of lead, degrading the intelligence of thousands of kids.

But new regulations were going to be costly and complicated. So, "instead of trying to deal with it substantively, they just tabled it," Levin, a former EPA researcher, said of some of her colleagues at the agency in the 1980s.

Levin's analysis then was leaked to the press, igniting a public outcry that pressured the EPA to act. And the rules it issued back then have stayed in place, with only modest changes, ever since.

Now, the EPA is on the eve of strengthening them.

Decades after officials banned lead in gasoline for new cars and stopped the sale of lead paint – huge steps toward eliminating significant sources of lead exposure to the public – there are still an estimated 500,000 U.S. children with levels of lead in their blood that are considered high, and experts say lead in drinking water is an important source.

Now the agency is aiming to further reduce lead levels in drinking water and tighten a rule that failed to prevent recent drinking water crises in cities like Flint, Michigan, and Newark, New Jersey. Although the specifics aren't public, the agency says it will propose requiring that utilities actively replace harmful lead pipes.

U.S. President Joe Biden has already called for eliminating the country's estimated 9.2 million lead pipes, lines that connect water mains under the street to homes and businesses and are responsible for most of the lead that seeps into drinking water.

But it's costly to send out workers to dig up the pipe, lay new ones and replant damaged landscaping. In many cities, homeowners are expected to pay to deal with the pipe on their property.

"Across the population, this has huge effects," said Levin, who now teaches at Harvard University's school of public health.

Kids are especially sensitive to lead exposure and high doses significantly reduce intelligence, impair coordination and disrupt a student's ability to focus and learn. Behavior can deteriorate. U.S. federal officials say there is no safe level of lead for children, and even small amounts can reduce IQ scores.

The updated rules will arrive as the federal government attacks lead on several fronts, with announcements about the dangers in aviation fuel and proposed stricter limits on dust from lead-based paint in older homes and child-care facilities.

Decades of work have drastically reduced childhood blood lead levels in the U.S. But many kids are still being exposed to the toxic metal "and the expectation is that a fair amount of that is from lead in water," said Dr Aaron Bernstein, a Boston-based pediatrician who this year became the head of the Centers for Disease Control and Prevention's environmental health programs.

Bernstein said he is hopeful "that as we remove lead pipes, we're going to see the numbers continue to fall. And that will be really wonderful."

(Cover image via CFP)