The Environmental Protection Agency finalized a rule Thursday to tighten lead dust standards. The move aims to eliminate decades-old paint in millions of homes across the country that endangers young children.

The new rule declares any amount of lead dust detected on the floors and windowsills of homes as hazardous. The rule could trigger extensive cleanup once a doctor, public health official or other expert identifies signs of lead exposure depending on state and local laws.

It establishes an aggressive new standard for cleanup that would reduce lead to the lowest detectable levels that can be reliably measured in a lab but would not require inspections of homes that may have lead paint.

The rule marks another landmark step in the Biden administration’s efforts to minimize lead exposure, following a groundbreaking decision earlier this month to remove all lead pipes from U.S. households within the next decade.

“The science is clear,” said Michal Freedhoff, EPA assistant administrator of the Office of Chemical Safety and Pollution Prevention. “With this rule, we’re cementing the recognition that there’s no safe level of lead in blood.”

The EPA estimates that 31 million housing units, more than a third of all homes in the United States, still contain lead-based paint, which was banned in 1978. About 3.8 million of the homes have one or more children under the age of 6 living there.

Lead exposure – even at a low level – can cause serious developmental delays and other lifelong effects on children such as hearing and speech challenges. Lead paint can have a sweet taste, and children sometimes swallow it after putting their hands on surfaces and then in their mouths.

Biden administration officials say that Americans around the country – especially the most vulnerable, some of whom live in older homes that still contain lead paint – are grappling with the lingering effects of this legacy. Lead dust can be created when lead paint crumbles or is disturbed.

The EPA estimates that the rule will reduce lead exposure for up to 1.2 million people every year, including up to 326,000 children under the age of 6.

In 2021 the Centers for Disease Control and Prevention lowered the threshold for blood lead levels that would trigger medical and public health interventions from 5 micrograms per deciliter to 3.5. But CDC officials say there is no safe level of lead in blood.

Ruth Ann Norton, the president and chief executive of the Green and Healthy Homes Initiative, applauded the EPA for taking actions to limit exposure to lead paint. “This is a step in the right direction,” Norton said.

But she added, “We’re not done.”

Even in communities whose children face the highest risk for lead exposure, however, some worry whether they can eliminate it.

Landlords have said the rule would limit affordable housing because it will cost so much to meet the new standards.

But Freedhoff say the “benefits outweigh the costs” and that it is a “false choice” to make children choose between a safe home or no home at all.

Nicole Upano, assistant vice president of housing policy and regulatory affairs for the National Apartment Association, said that while landlords want to reduce childhood lead poisoning, the rule “places the sole onus on the nation’s housing providers to remediate dust levels to absolute zero.”

Upano added that the new standards enforce “an impossible task.”

Child-care providers have also raised concerns about the cost of complying with stricter standards, because the new rule applies to child-care facilities and other spaces routinely used by children under the age of 6, such as preschools.

Cindy Lehnhoff, who directs the National Child Care Association, said the industry is already struggling to provide affordable care and has a shortage of licensed child-care centers and homes.

Lehnhoff said the rule will “protect some young children in child care but will also create an unaffordable expense that will require government funding to implement.”

Still, public health advocates argued that the new standards were overdue. The EPA moved to revise the rule after Earthjustice and other groups sued the agency in 2019, alleging it had failed to protect children from harmful lead exposure.

While a future administration could seek to overturn stricter limits on lead paint exposure, Kelly Lester, a senior associate attorney with Earthjustice, said it would not hold up in court because it was updated to protect human health in accordance with the Toxic Substances Control Act.

Oceanna Fair, the co-chair of Families for Lead Freedom Now, an advocacy group based in Syracuse, New York, said the new rules will prevent children from being poisoned. But for her, new standards won’t undo what her own family has had to endure.

Her younger brother was exposed to unhealthy levels of lead as a child more than 40 years ago. Every day from the time he was 2 years old to 13, she recalled, he had seizures. Decades later, after rain caused the white and brown chipping paint on the backside of Fair’s house to contaminate the soil, her granddaughter was poisoned after making mud pies there.

“It is very frustrating because as a parent, as a grandparent, you always want to protect your children and your grandchildren,” Fair said.

“We don’t want to see anybody else go through this,” she added.