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The lead-poisoning data gap

Marissa Ortega-Welch
Antonio Godinez plays while his mom Anabel Razo fills out paperwork for his blood lead test.


This is the third story in our four-part series  “Persistent Poison: Lead’s Toxic Legacy in the Bay Area,” an in-depth look at childhood lead poisoning in the Bay Area.

The numbers show the lead poisoning problem in the Bay Area is bad — but is what we know just the tip of the iceberg?
Part I: Living with lead poisoning in the San Francisco Bay Area
Part II: Lead and the Bay Area housing crisis
Part IV: A lead-poisoning solution within reach

First step, the blood test

Lead-poisoned kids make their way into the public health system if their doctors order blood tests.

These blood tests typically happen when kids are pretty scared of needles,  around their first and second birthdays. Those are the most likely ages for exposure, when kids are crawling around on the floor, putting their hands in their mouths. If kids get lead poisoning at this young age, it’s dangerous for their future. Their brains aren’t fully developed yet.

Credit Marissa Ortega-Welch
Anabel Razo holds her son Alex as he gets a blood test.

Blood is tested for lead in a lab. If it comes back with a level of anything above five micrograms of lead per deciliter of blood, the results get sent to the California Department of Public Health (CDPH), and the Centers for Disease Control and Prevention (CDC), and the child is added to a statewide list of lead poisoned children. For example, in Alameda County in 2014, at least 400 kids under the age of six who were tested made thatlist. Statewide, nearly 9,000 children did.

Here’s the catch


Not only does the CDC say that any amount of lead is unsafe, these statistics don’t reflect the true number of kids with lead poisoning.

This test isn’t given to every single one and two-year-old in California.

The only children required to get blood tests for lead are those with families on public assistance.Thereasoning behind this is that kids on Medi-Cal or other types of public assistance are usually lower income, and lower income kids typically live in older housing with older paint –– the kind with lead in it.

In many cases, in order to get benefits from the state, families must prove their children were tested for lead at those ages.

What about all other kids?

The American Academy of Pediatrics, the CDC, and the CDPH all created guidelines and recommendations about when and if doctors should run tests.

Most doctors decide whether or not they should test a child for lead by asking their family questions about their living situation to try to flesh out their potential lead risk. If a doctor suspects lead exposure, he or she orders a test.

Still, we wondered: is every child who should get tested, getting tested?

To figure this out, we started doing some digging, asking the CDPH to send us the number of kids tested for lead poisoning –– and the ones who actually tested positive for lead –– in every single zip code in six Bay Area counties.

Once we got this data back, we took the numbers and our questions to a Larry Brooks, the director of Alameda County’s Lead Poisoning Prevention program.

Larry greeted us with a strong handshake and a big smile. He is soft-spoken and very patient, the latter a quality that pays off in his line of work. Because lead paint was banned in 1978, some people can’t believe his job still exists.

We showed him a spreadsheet of the top 70 zip codes with the highest percentages of lead poisoned children in the Bay Area. Most are in Alameda County, but we know not every kid in the county’s been tested.

Larry took a look and asked: “What if all the children in these zip codes were tested? What would the percentage look like?”

If we tested all kids for lead poisoning, would the problem be worse than we thought?

So, we filed more info requests, continued hounding the CDPH, and the California Department of Healthcare Services.

We got lots of numbers back, but also ended up hitting a lot of dead ends. We just needed more data that doesn’t exist.

But, they say when one door closes, another one opens, and behind that door was Daniel Madrigal. He’s a health educator with the California Environmental Health Tracking Program, which collects data on environmental health factors: asthma, birth defects, pesticides, and most important for us, childhood lead poisoning.

Daniel published a study last yearthat asked and answered questions similar to ours, including: how well is the country doing at finding the kids with elevated blood lead levels?

He says, what we're finding is that the U.S. is not doing a terribly good job at it.

A big lead-testing gap

Daniel’s team came to this conclusion after creating a scientific model that uses census data and risk factors— like how much a family makes and where they live –— to estimate how many kids in the U.S. probably have lead poisoning. Then, they compared those estimates to the numbers that currently exist, the reported number of kids who tested positive for lead poisoning.

Their model indicates there are many more kidswith lead poisoning out there than the official, government numbers reveal.

Credit Public Health Institute 2017
A graph from Daniel Madrigal's team's study, "A Hidden Problem: Lead-Poisoned Children in the United States (2017)."

“That's a big gap,” Daniel says. “That's like saying one in three kids in the U.S. are not being tested, and they're just going through their lives unaware that they're facing these additional challenges. We're all pretending like  they’re able to reach their full intellectual capacity and that might not be the case.”

Different states have different ways of collecting lead poisoning data. Some send their information to their state public health departments, others send data directly to the CDC. Other states store it within the county hospitals records, and some states don’t even make their data public. The national picture is a bit foggy.

However, Daniel has data on California. His model suggests our state has an even bigger gapthan the national average.


"Kids aren't being tested. It's pretty simple." - Daniel Madrigal

He believes that if more kids were tested, we’d find many more kids with lead poisoning, almost three times more than the 400 kids in Alameda County and more than the 9,000 reported in California.

So, why aren’t more kids getting tested?

Daniel Madrigal says, some doctors don’t ask, and some parents don’t know to ask.

The questions that determine if a child should get a test in the first place are difficult to answer. For example, do you know the year in which your apartment was built?

Diep Tran, the public health nurse who works with all of the reported lead poisoning cases in Alameda County, says doctors might not be asking enough questions. Right now, many doctors use a family’s income to decide if a child should be tested for lead, based on recommendations from the American Academy of Pediatrics, the CDC, and the CDPH.  

“The rationale behind this is that low-income children tend to live in the dilapidated houses with peeling paint,” Diep says.

This is the “classic profile” for lead poisoned children: poor kids living in old, run-down houses. So, doctors often only test for lead when they think their patients fit that profile.

Paint is still the cause of the vast majority of lead poisoned cases. Diep thinks if doctors think that’s the only cause, though, they might overlook children who don’t fit that “classic” profile, kids poisoned due to what Alameda County calls “cultural lead hazards.”

“Lately we've been receiving referrals on middle-class and upper-middle-class children with cultural lead hazards,” Diep says. These can come from products that can contain lead, like turmeric from India, eye makeup from Afghanistan, or some clay pots from Mexico.

Credit Marissa Ortega-Welch
This is the 'lead museum' at the Alameda County Health Homes Department. All of these products have lead in them.

“This is such a big country and we keep getting new immigrants daily. In each culture, an ethnic group comes with their own sources of lead poisoning. So, in that case, we depend on the doctors to do the screening in the office, if the child recently immigrated to the U.S.,” she says.

Diep tells us awareness is growing, and doctors are beginning to ask questions about these products. That makes us wonder, instead of requiring doctors to remember a lot of different questions, wouldn’t it just be easier to test every kid for lead, regardless of where they live, where they came from, or how much money their parents make?

Universal testing

California nearly mandated this type of solution.

“There was a bill in the Assembly last year that was going to move towards a system of universal testing,” researcher Daniel Madrigal says.

By the time the bill passed, the universal testing mandate was taken out. It does require new questions for doctors to ask, to catch more children at risk. Daniel, and the doctors we talked to, think asking more questions will be difficult to enforce.

“This problem will continue, and we will continue to have children who have these elevated blood levels and who aren't kind of taken care of by the public health system,” Daniel says.

Some insurance companies and physicians associations oppose the idea of universal testing, saying the state shouldn’t legislate medicine, and doctors would just be wasting time and money testing kids that don’t have lead poisoning.

Many kids are required to get blood tests for anemiaat a young age. Adding on a lead test would cost about $20 more per child.

What would take time — and more money — is setting up databases and recording all of that new information. Each county and state tests for lead a tiny bit differently, so getting it all to match up would be a lot of work, Daniel says.

He argues, even finding one kid with lead poisoning who normally wouldn’t be tested would make universal testing worth it, and it would help us get a better sense of the problem.

“We need to understand the scope and how much how much damage it's causing right now,” he says.

Testing everyone has its limits

Many critics say it’s unethical to test a bunch of children, without having a plan in place to treat the bigger problem. At this point, they argue, states and counties don’t have the resources to make sure there’s adequate treatment for lead poisoning.

Daniel says he understands this position. “Universal testing isn't going to take lead out of a house. It's not going to save a child. It's not going to protect them from being poisoned,” he says.

Instead, some critics say we should start by testing certain city blocks, or neighborhoods identified as high risk where it may be more manageable for public health workers to do intensive interventions and counseling in families, and in specific communities.

Right now, most kids make it into the public health system with elevated blood lead levels before the source of lead is even identified.


"So we're treating them as the canaries in the coal mine and waiting for the damage to have already been done in some way or form before starting prevention." - Daniel Madrigal

"We’re sentencing these kids to these lifetimes of lead exposure,” Daniel says.

The real solution, he thinks, is a system to address the problem of lead in homes before kids get poisoned. It would take a lot to actually to remove sources, since 80 percent of Oakland homes were built before lead paint was banned. However, Alameda County officials have a solution for that,  one they’ve been trying to get Oakland to adopt for almost a decade. Tomorrow, in our final installment in this lead series, we will look at one solution to the Bay Area’s lead crisis.


This is part of our series “Persistent Poison: Lead’s Toxic Legacy in the Bay Area,” originally broadcast on March 28, 2018. To find a list of resources on lead poisoning, click here.  

Angela Johnston is the Senior Producer of Uncuffed and an editor in the KALW newsroom. She holds a Master’s degree in journalism and graduated from KALW’s Audio Academy program. She’s worked for KALW in numerous roles - from the deputy news director, to the health and environment reporter, and she's covered everything from lead poisoning to climate change. Her work has aired on KALW, KQED, Reveal, and The Pulse. She also freelances as a producer and editor for Cosmic Standard and AFAR Media. Outside of work, she loves to swim in the bay, surf small waves on her longboard, read, backpack, cook, and garden.