Although it was banned nearly 40 years ago, lead paint continues to cause problems each year for thousands of Massachusetts children, threatening to cause permanent brain and kidney damage.

“Kids are considered to be at the greatest risk because their nervous systems are still being developed and organized,” explained Dr. David Bellinger of Boston Children’s Hospital. “Lead interferes with the structural development of a brain. You want a brain to develop in the absence of lead.”

In 2015, the most recent year for which statewide data is available, more than 3,500 children ages 5 and younger, or 17 out of every 1,000, tested positive for blood-lead levels of 5 micrograms per deciliter or greater. That reference level is the threshold the federal Centers for Disease Control and Prevention uses to designate an elevated level of lead exposure.

That number is down sharply from 2001, when 16,202 Massachusetts children, or more than 83 out of every 1,000, tested positive for blood-lead concentrations that exceeded the CDC’s current reference level. Experts attribute much of that progress to steps taken in the previous decades, such as phasing out the use of lead additives in gasoline and solder.

Still, the presence of lead paint in homes built before 1978 remains a concern. The primary source of lead exposure is lead paint dust, said Terry Howard, acting director of the Massachusetts Childhood Lead Poisoning Prevention Program, which is overseen by the Department of Public Health. When lead paint chips or deteriorates, the lead can settle and mix with dust. Children can then be exposed by touching or inhaling the dust.

“We have a very old housing stock, and we do about 8,000 lead inspections a year,” Howard said.

Pre-1978 homes make up about 71 percent of the housing stock in Massachusetts. While much of the inspection data from the 1980s and ’90s isn’t available in a digital format, DPH records indicate that 335,521 homes have been inspected for lead. That’s just 17 percent of all homes built prior to 1978.

Additionally, the DPH estimates 90 percent of pre-1978 housing stock in Massachusetts has yet to report any deleading activity. 

The Trump budget effect

The 2014 drinking water crisis in Flint, Mich., brought renewed national attention to the dangers of lead. President Donald Trump’s proposed federal budget cuts, which would eliminate the Environmental Protection Agency’s Lead Risk Reduction Program, has also pushed the issue of lead into the spotlight.

U.S. Rep. Joseph Kennedy III, a Brookline Democrat, sent a letter to EPA Secretary Scott Pruitt, urging him to preserve the program, which trains building renovators on safe paint removal.

“The data we have indicates this is a huge problem around the country,” said Kennedy. “I think governments at all levels have a responsibility to address this. The bottom line is when you have a young child exposed to lead, they’re going to suffer with the consequences of that for the rest of their lives.”

Massachusetts relies on a combination of state and federal funding sources for its lead risk reduction programs, while 36 other states rely entirely on the EPA funds that have been targeted for elimination.

Lead exposure disproportionately affects children from low-income families.

“We’ve got communities in Massachusetts where the rate of lead contamination is double or triple that of Flint,” Kennedy said.

In several communities, the rates of exposure to elevated lead levels are heavily concentrated in certain neighborhoods. New Bedford, Brockton, Milford, Fall River and Worcester, for example, all have census tracts where more than 10 percent of children have blood-lead levels higher than 5 milligrams per deciliter, much higher than overall exposure rates across the entire community.

Statewide, about 3 percent of children under age 4 tested positive last year for elevated blood-lead levels. In Flint, Mich., the exposure rate was 5 percent. 

The state law and the future

The Massachusetts lead law requires that homes with children under the age of 6 be lead free, and that the seller of any home disclose any known lead issues. But the vast majority of older homes remain untested. A lead inspection could trigger expensive deleading work, which could cost upward of $10,000 depending on the circumstances.

“I think there’s a loophole in terms that sellers are required to provide what they know, and that actually provides a disincentive to test,” said Bellinger.

Under Massachusetts regulations, a child with a blood-lead level of 25 micrograms per deciliter or greater is considered to have lead poisoning. At that point, the blood test results trigger mandatory code enforcement interventions including inspections and deleading.

Lead poisoning can cause a drop in IQ, developmental delays and neurologic changes. It doesn’t always produce symptoms, but people with lead poisoning may experience body aches, fatigue, nausea, abdominal pain, irritability and insomnia.

The DPH initiates case management for children with a blood-lead level of 10 milligrams per deciliter, but parents have the option to refuse those services, which could include home inspections and community health worker outreach.

Massachusetts has pending proposed regulations that would redefine blood poisoning to include blood-lead levels of 10 milligrams per deciliter or higher. The proposed regulations would also label a blood-lead level of 5-9 milligrams per deciliter a “level of concern.”

Bellinger, the lead expert at Boston Children’s Hospital, said he’d like to see the federal government strengthen its approach to lead.

“Millions of U.S. homes still have lead paint somewhere in them,” said Bellinger. “I think the measures we’ve taken have produced a tremendous benefit, but if we relax our vigilance, I think there is a danger the problem will rear its head. My position is that the government shouldn’t relax its regulations and programs, but actually heighten them.”