Welcome to Paging Dr. Gupta. You know, I've come to think of this as my office hours where we all sort of huddle around and chat and thanks to so many of you for joining us every week here. I take your health questions, they take center stage. I try and make sense for you of the health issues that matter most to you. You know, this week I was in Milwaukee. There's been a troubling discovery in the city's public schools that has parents and teachers and health officials pretty concerned. It's about lead paint. Each year, about 1,000 children in Milwaukee test positive for lead poisoning, 1,000 kids. It's because many of the buildings are aging, but at the same time, they are still open, still full of students, and still part of daily life. It's a challenging problem. I just got back from that assignment, and I wanted to share some of our reporting with you. Not only what I saw on the ground, but I think what you need to know about lead exposure and how it can affect children and adults alike.

'Any building built before 1978 in America probably has lead-based paint in it, which could poison kids. Our story starts here, Milwaukee, in January. A kid was found to have four times the amount of lead in their blood as expected, so they started to investigate, and they did not find any lead in the child's home. And for the first time, they were able to link lead poisoning in children to the city's aging schools. Specifically, they found evidence of lead containing paint in the elementary school bathroom. Since then, at least three more children have tested positive for elevated blood lead levels, and eight schools have also been found to have unsafe lead levels as well. In fact, here at Westside Academy, these kids had to be relocated to another school just this week. They found evidence of red flaking paint on the outside and lots of problems on the inside, paint that was flaking on doors and walls and window sills. City's now got a big job on their hands. They have to inspect around a hundred buildings.

So while I was there, I met with Milwaukee's commissioner of health, Dr. Mike Totoraitis, to better understand how this was happening. These shavings of paint, they're sweet. They taste sweet. Is that why kids eat them?

Yes, so they actually have a sweetness to them. So that's why we're generally concerned about children under the age of six who are crawling around on the ground and constantly putting things in their mouth.

What is the lead actually doing in the body?

'That gets absorbed into the bloodstream and can cause long-term cognitive delays and behavioral issues.

Do you guys have enough resources to accomplish what you need to do?

'We have enough of a team right now. I think the long- term investigation into the potential chronic exposures of students at the districts is a part that we were really looking to the CDC to help us with. And unfortunately, HHS had laid off that entire team for childhood blood exposure. These are the best and brightest minds in these areas around lead poisoning and now they're gone.

So for now, the city is trying to do the best that they can. In fact, they've set up a testing clinic here at this high school to screen up to 300 children today. Basically, the kid comes in, they sit down, there's a little lancet here that they do a finger prick test on. It goes into this machine over here and they will get a result back right away. Basically then telling the parents, look, your kid's lead level may be too high.

And I implore you all to shift to prevention, not reaction.

'While we were at the screening, a parent-led group gathered nearby making some demands about lead remediation.

My grandchildren have the right to go to school without the threat of exposure to lead.

'Now you should know that one of the most cost-effective and straightforward ways to control exposure from old paint is to paint over it. But schools in the school district fell behind, and now the superintendent is under a lot of pressure to get this done. I also met up with Milwaukee's public school superintendent, Dr. Brenda Cassellius. She showed me first-hand some of the exposure sites. This is particularly concerning if it's down low like this.

That's right, because it's where kids handle their materials. And if you're pulling things out, you could certainly just chip. So we remediated these surfaces, and then now we have to go back and paint it. But it's a constant cleaning, a constant upkeep, a constant painting. Painting a room can cost $800. We've got tens of thousands of square feet in just one school. We anticipate this could cost up to $20 million.

Do you have the money?

Well, we do in our reserve. So right now, I'm just saying I need to just spend every dollar. We are working with urgency and we are not sparing any expense because one student with lead is too many.

This was just a glimpse of what families and officials are facing in Milwaukee right now. After we aired the story, we started getting questions, lots of them. Questions about how lead affects a body, whether adults should be concerned as well, and even some surprising places that lead might show up. So after the break, I'll be joined by my producer Kyra, and we're going to tackle a few of the questions that we heard from you.

Well we are on the ground here in Milwaukee getting a lot of questions about lead. Something I wanna clarify right off the top because a lot questions came in about this. There is no safe amount of lead. That is something that you hear all the time. It's important to know. But at the same time when they test for lead the sensitivity of the equipment is to really around 3.5 micrograms. So that's the number that you often hear as an acceptable limit but that really has to do more with the testing than the actual limit of the lead in the body. Let's try and get to as many of these questions as we can. Kyra, who's up first?

Hey Sanjay, so first up we have Caryn from California and she wrote in asking something that a lot of other people were wondering, and that is, does lead ever actually leave the body?

'A really important question, the short answer is yes, lead does leave the body, but important things to keep in mind...First of all, it can continue to accumulate at the same time that it's leaving your body. So it can be going sort of back and forth. It is stored in the blood, it is stored in soft tissues, it's stored in your organs. But in adults, about 95% of the lead is actually stored in your bones and your teeth, and it can mobilize throughout your life, which is why lead can also be considered sort a long-term toxin. That is part of the problem. So it can cause problems throughout your life, but the half life is around a month and it does sort of leave your body as long as you don't continue to accumulate it.

Alright Sanjay, next up we have a question from John in South Carolina, and he's wondering, you know, while we often hear about how dangerous lead exposure is for kids, what about adults or seniors? Is it still a big concern?

You know, we do talk a lot about kids. And part of the reason we talk a lot about kid is because kids are smaller. So when they get lead exposure, it can have more of an impact on their bodies. Also, kids are closer to the ground. That's often where the lead dust is. Kids like to eat paint chips because paint chips are often sweet. So for all those reasons, lead exposure can have a bigger impact on kids than adults, but it can be a problem in adults as well. It does tend to leave your body as we just answered in the previous question, but in adults, it can cause problems if you get significant lead toxicity, including problems with your cardiovascular system and your cognitive system as well, your central nervous system. Let's get to one final question.

Okay, this last one is coming from Barbara in Vermont. And I just have to include this question because honestly, I'm so curious now too. And she wants to know how much of a problem is lead in chocolate? And like, can we continue to enjoy it while reducing exposure?

'All right, a lot of comments about lead in chocolate. Some heavy metals do end up in chocolate, lead, cadmium, even small amounts of arsenic. It has to do with the fact that these foods are often grown in soil that might be contaminated with lead. So if you go and you look at chocolate, for example, arsenic's not as big a problem, but if you look a lead, for examples, in chocolate the most strict standards, California standards, you'll find that about 43% of the chocolates out there do have levels of lead that would exceed those standards. So 43%. Now, that does sound concerning, but you got to keep in mind, again, there are a lot of heavy metals in all sorts of different foods. What they sort of concluded was that if you're eating only about an ounce per day, shouldn't be eating more than an ounce for a day, then you should not be getting enough lead to really be of concern. So the answer, Barbara, lead is present in chocolate. It's of concerning levels about 43% of the time in chocolate, But if you're eating just around an ounce per day or less, it should not be a problem for you. Hope that helps. And that's it for today's Paging Dr. Gupta. If you have other health questions on your mind, I wanna hear them, record a voice memo, email it to asksanjay@cnn.com, or give us a call, 470-396-0832, and leave a message. Thanks for listening. I'll be back next Tuesday.

Chasing Life is a production of CNN Audio. Our podcast is produced by Eryn Mathewson, Jennifer Lai, Grace Walker, Lori Galarreta, Jesse Remedios, Sofía Sánchez, and Kyra Dahring. Andrea Kane is our medical writer. Our senior producer is Dan Bloom. Amanda Sealey is our showrunner. Dan Dzula is our technical director, and the executive producer of CNN audio is Steve Lickteig. With support from Jamus Andrest, Jon Dianora, Haley Thomas, Alex Manassari, Robert Mathers, Leni Steinhardt, Nichole Pesaru, and Lisa Namerow. Special thanks to Ben Tinker and Nadia Kounang of CNN Health and Wendy Brundige.