“I’ve been consuming [that Lead-contaminated thing] every day, but my Blood Lead Level (BLL) test came back negative. How is that possible?”

  

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The image below is my quick social media response to this question (continue reading below the image):

Always ask your doctor about any medical testing you are considering.
This link has more info on urine testing.

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For those new to the Lead Safe Mama website:

Tamara Rubin is a multiple-federal-award-winning independent advocate for childhood Lead poisoning prevention and consumer goods safety, and a documentary filmmaker. She is also a mother of Lead-poisoned children (two of her four sons were acutely Lead-poisoned in 2005).

• Tamara owns and runs Lead Safe Mama, LLC — a unique community collaborative woman-owned small business for childhood Lead poisoning prevention and consumer goods safety.
• Since July 2022, the work of Lead Safe Mama, LLC has been responsible for six product recalls (FDA and CPSC).
• All test results reported on this website are science-based, accurate, and replicable.
• Please check out our press page to see some of the news coverage of our work, linked here.

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Published: April 16, 2025

“I’ve been consuming [insert Lead-contaminated product] every day, but my Blood Lead Level (BLL) test came back negative. How is that possible?”

I have written this piece (below) to provide a more detailed response to this commonly-asked question (a question I have answered briefly on social media quite a few times, as shown in the image above). The response below is for a specific question about matcha, however I have written my answer so that it applies to this consideration more generally (as it relates to any ingested product that tests positive for Lead).

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Section #1) Some Background

My friend “Q” (initial changed for privacy) asked us to test a product that their older (teenage) child consumes frequently. That product is DO Matcha (you can see the full lab report for it at this link). The social media-sharable graphic with the lab results for that product is below:

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When comparing this DO Matcha Organic Ceremonial Matcha to other, similar matcha products we have sent to the lab for testing (through the Lead Safe Mama, LLC Community Collaborative Laboratory Testing Initiative), not only did Do Matcha test positive for Lead, Cadmium, and Arsenic, but it also tested positive for one of the highest levels of Lead of all the matcha products we have tested.

Here’s the most recently published iteration of our comparative chart showing all of the test results for the matcha products we have tested to date:

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After I tested this product for Q, they shared our findings with a friend, “Z”. 

Z took a look at the test results and the lab report and had some questions, which she shared with Q.
Z’s comment (edited slightly):

“I had bloodwork done for myself (and so did a few others I know who drink this DO Matcha product) and all metals tested negative (so, it’s so far below <1.0 that it doesn’t show up). I’m wondering if the test results are batch dependent, because Purity is supposed to be a reputable lab.”

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Here’s my response to Z’s question for Q (unpacking things a bit, so the considerations apply to all similar questions we have received since we started this laboratory testing initiative in March of 2024). I am going to ask Q to share this link with Z, too!

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Hi Z!

Your note brings up several good questions, which I will try to answer below (as thoroughly as possible).

I do want to start by saying that if you (or anyone else you know) wants to have a deeper discussion about the considerations related to these concerns (specifically, persistent/ chronic, low-level toxicant exposure from food and beverage sources), I will be in Q’s neck of the woods in the second half of May and perhaps (if Q has some time then) we could chat over coffee about this issue in person — it’s always great to discuss these issues in real time, especially when it concerns a legitimately significant health-related issue. (Feel free to invite anyone else in your sphere who would like some straight answers and clarification based on the best/ latest science regarding these concerns!) In the meantime, I have made an effort to answer all relevant questions I can think of related to this inquiry below. I apologize for the length of this response (to a seemingly “simple” question!), but a genuinely meaningful and useful answer to this important inquiry actually requires — and deserves — more than a superficial response…

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#2) Lab Integrity

I want to thank you for acknowledging Purity’s reputation as a dependable lab — they are! We have found that not only does Purity have very high standards, but they are also excellent communicators! These were only two of the deciding factors in Lead Safe Mama, LLC choosing to work with Purity, which we began doing last month (in March of 2025) for segments of our Laboratory testing initiative. Interestingly,  the owner of Purity has a background as a lawyer and has worked with Ralph Nader on consumer safety initiatives! He is also quite focused on/ committed to prenatal and preconception health, as well as the health of children in general. I have complete confidence in Purity’s scientific methodology and the accuracy of their testing.

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#3) Liability Considerations

As you are new to the work of Lead Safe Mama, LLC (LSM), I think it is important to share that our woman-owned small business (based in Portland, Oregon) has a high degree of vulnerability in the work we do — if we were to ever report false or flawed test results (i.e. results that were not scientifically rigorous and replicable), companies could easily sue and shut us down. 

It’s an interesting conundrum, actually… Despite the fact that we ONLY report accurate, replicable scientific test results (with 100% transparency) — and consequently, no company can legitimately attack us successfully for “sharing ‘misinformation'” (and we are also not only very transparent about the information we do share, but also intentional/ mindful about how we present it) — periodically companies do accuse us of allegedly “sharing ‘misinformation,'” and try to intimidate us with threats of lawsuits. We have an extensive collection of “cease and desist” letters, which typically reveal a profound ignorance of basic science and that I actually find rather amusing. But since we only share replicable science (alongside the context of accepted standards published by scientists, medical practitioners, and/or relevant federal agencies), this “saber rattling” never leads to anything.

The irony behind this conundrum  is that because our work is pushing limits and boundaries (because there are almost no other agencies or organizations out there sharing raw, unbiased, direct-to-consumer science), we have actually been unable to secure liability insurance for our business(!). Thus, IF a company were to successfully sue us, we would stand to lose everything. This is another reason why we are so careful about the language we choose in sharing science, making sure each and every statement stands on its own (especially if it were to ever be questioned in a formal legal challenge). It is also for this reason that our readership and online community (nearly 2.3 million unique individual readers around the world in 2024 alone) trusts LSM to fairly and accurately share the information we uncover through our independent, community-directed, community-funded testing initiatives.

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#4) Batch-SpecificVariation

This brings us to your concern about potential batch-specific variation. If we ever suspect that a test result might in fact be an anomaly (whether due to potential batch issues, or other factors), we do not publish those results. Instead, we re-test the product (re-submit to the lab and wait for the results of a second test to confirm before publishing).

While some batch-to-batch variation in test results can be expected, for the nearly 400 products we have tested in the past 13 months, whenever the companies producing these various products have published their own lab-testing results, our lab test results have always closely matched theirs (within a reasonable margin of error) — as we would expect. 

So, while the DO Matcha result of 115.7 ppb Lead may represent a level that could vary to some degree batch-to-batch, given all of the data points we have collected to date (including both evaluating other available scientific research about matcha contamination and confirming the possible range of contamination via the product-specific laboratory testing we have coordinated through this community-funded initiative), we don’t expect the range of Lead in this product to vary to any significant degree. (Do Matcha is also, by definition, a commercially–manufactured, processed, packaged food and therefore follows a set of considerations that also limit batch variation.)

Said another way: With a laboratory-confirmed level of 115.7 ppb Lead, absent some unusual extreme contamination “event” leading to an unexpected spike in the levels for this product, I would expect the variation of Lead in other batches to fall within the range in the order of 86 to 145 ppb (+/- 25%  — a range statistically supported by all of the other matcha product testing we have completed).

A separate example to illustrate our logic and methods: Last year we tested one product for which I found the result (“non-detect” across the board for heavy metals with a low threshold of detection of 10 ppb) quite surprising, and given our research on this specific product-type (based on the ingredient profile), I suspected this was likely an anomaly. So accordingly, I decided to re-test the product. The second test (with our testing always conducted blind so the lab does not know what product it is testing — or in this case, re-testing — for us, ensuring there is no possibility of real or perceived bias ) came back positive for Lead within the expected range, confirming that the first test indeed represented an anomaly (likely due to a lack of homogeneity with the first sample we sent to the lab).

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#5) A Blood Lead Level (BLL) of “<1.0”

Now to address the blood Lead testing piece of your question… 

The most important thing to understand is that a blood Lead level (BLL) test result of “less than one microgram of Lead per deciliter of blood” is not sufficiently-precise for the purpose of this inquiry. (And most doctors are not aware of this.)

While BLL testing technology is actually capable of reliably testing down to a low threshold of detection of 0.1 micrograms of Lead per deciliter of blood or lower, most BLL testing labs today (in 2025) are setup with the capacity to report only down to a low threshold of detection that is one of the following numbers:

• “<5.0”
• “<3.3”
• “<3.0”
• “<2.0”
• or “<1.0”

For some context on the above numbers — which are truly insufficient low thresholds of detection to determine if one has had any noted level of Lead exposure from food-based/ ingested sources — the “natural” pre-Industrial Revolution average BLL for a human being has been determined (through historic bone analysis, primarily) to statistically be around 0.016* (here’s an article discussing this stat in more detail). This is also discussed in detail in my documentary film on childhood Lead poisoning, which is linked below. A BLL of 1.6 is 100 times that pre-Industrial Revolution level. When my son (who was acutely Lead-poisoned at 7-months-old) was first tested, he had a BLL of 16 — notably 1,000 times this “natural” level.

*Years after scientists came to this determination (the “pre-Industrial Revolution level of 0.016”), researchers at Harvard determined that the actual natural BLL — the BLL of humans before mining and refining of metals began as a human practice/ before those activities began polluting our atmosphere — was in fact even significantly lower than 0.016. (Here’s an article about that research.)

The average “background” level of Lead for American children today is in the range of 0.4 to 0.6 (range being dependent on community-related exposure factors). However, in May of 2012 Dr. Felicia Rabito — one of the scientists interviewed for my film — announced her groundbreaking, new at that time (not-yet-published) findings at the National Lead Poisoning Prevention Conference in New Orleans, an event where I was the Keynote speaker. She revealed how population-level data related to women of childbearing age showed that even a BLL of 0.43 (the average BLL of women of childbearing age) has negative impacts on fertility and birth outcomes (with statically-significant increases in adverse birth outcomes occurring even with slight increases in increments of 0.1 micrograms of Lead per deciliter of blood).  You can read more about that here, and here’s a link to one summary of Dr. Rabito’s findings.

Given the above background, it is important to note that persistent/ chronic (daily), low-level/ trace (ppb, levels) exposure to Lead from most food or beverage sources will not often result in a BLL of 1.0 or higher**.

**The exceptions to this are individuals whose diets include significant daily consumption of cassava flour (or cassava-flour based products), dark chocolate, sweet potatoes, cinnamon, certain seaweed products, or other known heavily-Lead-contaminated foods. You can read more about that here.

While it is EXCELLENT that you took the first step of getting a BLL test, and a great result that your lab reported a BLL of  “less than 1.0 micrograms of Lead per deciliter of blood,” (“great” as far as that goes, since most doctors don’t have access to labs that test for levels below that) this is simply not a sufficiently low threshold of detection to be able to rule out exposure from food-based and beverage-based sources — especially if those are known-contaminated sources consumed daily.

Here’s some additional reasons that, despite a potential significant ingested exposure-source of Lead, your BLL tested at “<1.0”: Because Lead bio-mimics calcium, combined with it’s relatively short “half-life” in the blood , even with persistent daily/ chronic low-level exposure it is more likely that the Lead you are being exposed to is no longer circulating in your blood  and has been absorbed (fairly quickly) by calcium-rich structures in your body (i.e. it is already deposited and incorporated into bones, organs, etc.). As a result, while this type of exposure may not present issues concurrent to that exposure, it can produce or contribute to long-term issues later in life (including impaired fertility and sexual function, compromised kidney function, increased risk of heart disease, arthritic conditions, neurological issues, and memory impairments/ cognitive function, just to scratch the surface ).

These impacts are all long-understood, scientifically-confirmed risks from Lead-exposure and are not shared to frighten  — they are shared to help encourage people to avoid choosing to consume any known Lead-contaminated products.

Note: Ask your doctor about getting a provoked urine test (if that might be appropriate for you, given other factors in your life). If a provoked urine test shows otherwise unexplained high levels of any heavy metals, this can be a good indicator that removing any sources of those metals is warranted. Provoked urine tests are not appropriate for all people (including pregnant women) and should only be done under the guidance of a medical provider. More on this here.

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#6) “How do you (Lead Safe Mama, LLC) evaluate if a product is ‘okay’ or not? What is the safe threshold of toxicants in ingested products?”

I think it is important to reiterate that our safety evaluations are not  “fear-mongering “/”alarmist”  but are rooted in science and fact; we share numbers (lab test results) as well as context for those numbers (existing federal regulations and relevant federal agency statements, proposed federal regulations, state regulations, public perception of the products based on corporate statements and marketing materials, as well as statements from the scientific and medical community, etc).

The foundation of our work is the understanding that there is no safe level of Lead exposure for human beings — this is a point of scientific consensus, acknowledged by all relevant federal agencies and all relevant scientific and medical bodies (even throughout the turmoil the current administration has imposed on our federal health-related agencies, there are still today published statements from the CDC, EPA, FDA, and HUD (on their websites) articulating the most basic guidance warning that there is no safe level of Lead-exposure for human beings. This is an unassailable fact. 

Additionally, it is important to know that Cadmium is a known carcinogen. It is our stand that with the rise in diet-related cancers (documented by several scientific investigations over the past couple of years), known Cadmium-contaminated products should not be consumed. This also goes for Mercury-contaminated products. If a product tests positive for Lead, Cadmium, or Mercury, you should see if you can find a product to replace it that does not test positive for those toxicants (with a low threshold of detection of 5 ppb or lower, if possible).

Our intention is that families will use this information to make evidence-based safer choices for their children. As context for our test results, we have provided the following safety threshold levels for people to consider:

• Less than 5 ppb Lead
• Less than 5 ppb Cadmium
• Less than 2 ppb Mercury
• Less than 10 ppb Arsenic

The levels above were proposed as standards with the  Baby Food Safety Act of 2021 as “Action Levels” that would be most health-protective of our youngest citizens. Unfortunately, this was not passed into law. However, the logic behind choosing these levels is still valid being they were proposed not because that amount of Lead (or other toxicants) is a “safe amount of exposure” (again, there is no safe level of Lead exposure!), but rather because those are the practical low thresholds of detection of most available laboratory testing  (accordingly, they represent the most commonly found low thresholds of detection on lab reports for ingested products). They are a good starting point in our journey to get “closer to zero,” with the understanding that while no level of exposure is safe, it is not possible to avoid all exposure. These exposure limits (for all ingested products) are a great starting point.

The common deflective argument made by manufacturers in response to LSM’s testing and reporting — that “levels proposed for Baby Foods should not be applied to products consumed by adults” — is actually irrelevant when one remembers there is no safe level of Lead exposure for humans, and that the impact of Lead-exposure is cumulative over a lifetime.

With the above in mind, if a product tests positive for toxicants at-or-above those thresholds, we hope that consumers will seriously reconsider their relationship with that product (and will perhaps also revisit their reasons for choosing that product). Can you find a safer alternative for this product type? Can you find a safer alternative that is a different product-type but fills the same function? (Take coffee instead of matcha, perhaps? This coffee product tested clean, as did this one, and this one, too. Or how about steeped green tea vs. matcha? This steeped green tea product tested clean.)

For context, it is also important to reiterate that the impact of Lead is cumulative over a lifetime. Lead bio-mimics calcium and is stored in the bones, brain, and tissues of humans (in any calcium-rich structure, the body absorbs all Lead present and stores it where it would store Calcium, diminishing those biological functions reliant on Calcium). 

Ultimately, this work is all about empowering families to make safer, science-based choices for their families — choices not influenced by corporate marketing spin or dietary fads. 

In short, if there is a toxicant-free alternative to a toxicant-contaminated product you are using, it is reasonable for you to consider choosing the cleaner product instead. It is our belief here at LSM that if you had this information prior to making a choice for your family, you would likely choose that cleaner alternative.

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#7) “Do you ever ‘cheat?’ What’s the impact of ‘cheating’ every now and then?”

Most people have a thing they are willing to “cheat” with. Here I am in France having the occasional Italian hot chocolate drink (but still NEVER eating dark chocolate). (Perhaps it is psychologically healthy to give yourself a “free pass” every now and then?) However, even your “cheats” will be less-potentially-harmful if those choices are informed by science.

Some examples (starting with my own, confessed, rationalized occasional cheat):

• Milk chocolate, diluted with milk (= hot chocolate) makes a much cleaner toxicant profile than pure chocolate alone (and particularly dark chocolate);
• Also, it is our sincerest hope that families in the Lead Safe Mama community will no longer feed their children seaweed snack sheets (based on our scientific testing), and will look for safer alternatives. Two favorite alternative savory snacks in our now seaweed snack-free home are organic cherry tomatoes with a little sea salt and organic garbanzo beans with a little organic red wine vinegar. (Links here lead to lab reports.)

Here’s the link to the list of lab-tested safer choices we have found to date through this laboratory testing initiative.

It’s truly a #KnowBetterDoBetter scenario — once you know better (informed through science), doing better is possible (and just makes sense when the future of our children’s health is at stake).

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#8) “So — have I been poisoned from using this product, then? What should I do about it?”

I would say that asserting a specific product is “poisoning you” is a bit of an alarmist oversimplification (in most, but not all cases). What you have been doing by consuming this product is adding to your overall cumulative body burden of heavy metals over time. Only time will tell if this personal choice is going to negatively impact your personal health.  

A better question to ask is this:“Would I have chosen to use this product if I knew it tested positive for toxicants, especially if I knew it tested positive for toxicants at levels that are significantly higher than what has been found in other similar products?”

The answer to that question can only be known by you personally. I am not going to “judge you”/ “make you wrong” for choosing to consume matcha. This is a very personal choice you are making. However, if (as a hypothetical example) you were, having say, fertility issues or birth complications and you came to me asking for advice on how to improve this situation for the future, I would review your consumption of known contaminated products and IF your diet included matcha products, I would advise eliminating them. (To continue that example, I would also advise you to avoid “detox protocols” and any packaged/ processed detox pills or potions. I would instead recommend the best natural food-based detox protocol (that has been scientifically demonstrated as more effective than even most pharmaceutical inventions!), linked here.

I would also advise you to read the following articles and watch my film 😉

• My doctor said my BLL was “normal”
• Can I infer my child’s BLL from my own?
• Half-Life of Lead in Blood
• How often should I test my child?
• I think I just exposed my kiddo to lead, should I worry about this?
• Is Urine or Hair Testing an option?
• Everything you should know about BLL testing before you get tested
• This page has all of the lab reports for our laboratory testing initiative linked in one place, too! (It’s a good page to bookmark as we updated it almost every day with new lab reports.)

All that said, products for which we have not yet found safe alternatives (products we therefore recommend avoiding, or significantly limiting/ finding safer choices to serve the same function) include: peanut butter, sunflower seed butter (and sunflower seeds, sunflower seed products), all forms of cinnamon, chocolate  and cocoa powder, matcha, cassava flour, rice (and rice-flour products), seaweed products, potato chips (and potatoes ), U.S.-produced/ grown wheat flour and flour products, protein powders, and prenatal vitamins (talk to your doctor about this to determine if you have a confirmed medical need requiring that you take prenatal vitamins, or if there are whole food dietary interventions you could use instead).

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#9) A deeper dive into the “why” behind this concern (from a mother of children with permanent brain damage from being acutely Lead-poisoned):

If you have not yet done a deep-dive into the concern of Lead-poisoning (including Lead-exposure of adults and the concern for persistent/ chronic, trace low-level Lead-exposure), I would encourage you to watch the documentary film I directed and produced on the subject.

The film has interviews with top scientists, medical doctors, researchers, policy makers, and others. It also shares stories of families with Lead-poisoned children across the United States. (For those who might be thinking, “whoa, that sounds rather dull,”  the film has music donated by The Who and Tom Waits as well as footage of my presentation at a packed Town Hall during a blizzard with then Presidential candidate Bernie Sanders during the  water crisis in Flint in 2016. There’s also footage of my interview with legendary linguist and dissident Noam Chomsky. Jon Fishman (drummer of Phish) is an Executive Producer of the project (we met when I helped his family after one of his children was Lead-poisoned). Here’s a link to the film on YouTube. It is also packed with actionable information for making informed choices for yourself and your family to live potentially healthier and longer lives.

Hopefully that answers all of your questions related to this testing and the reasoning behind our confidence in the levels, plus our concern for your “BLL <1.0” not being a sufficiently low threshold of detection to determine potential impacts from food-based exposure sources.

🙂

One closing thought: Product manufacturers will often argue that the safety levels we reference are “not achievable.” Through the LSM lab-testing initiative, we have definitively demonstrated that assertion to not be true. About 20% of the products we have sent to the lab for testing to date have tested “non-detect” for toxicants across the board (with the low-thresholds of detection noted).

Safer products are possible. Generating the political will required to shift the industry narrative and clean-up our food supply starts with consumer awareness.

Tamara Rubin
Owner
Lead Safe Mama, LLC