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 2009, Tamara has been conducting XRF testing (a scientific testing method) using the exact instrumentation employed by the U.S. Consumer Product Safety Commission to test consumer goods for toxicants (specifically heavy metals — including Lead, Cadmium, Mercury, Antimony, and Arsenic).
- Since July of 2022, the work of Lead Safe Mama, LLC has been responsible for 5 product recalls (FDA and CPSC).
- All test results reported on this website are science-based, accurate, and replicable.
- Items that Lead Safe Mama, LLC reports on are tested multiple times to confirm the results published (for each component tested).
- Recent Notable Press: Tamara’s work was featured in Consumer Reports Magazine in February 2023 (March 2023 print edition) and The Guardian in November 2023.
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January 6, 2023
Last Updated: September 13, 2023
In Summary: None of these types of products (reactive agent home test kits that purport to turn red in the presence of Lead) can be reliably used for testing consumer goods for Lead.
- The Chinese-branded knockoffs (the image above is an example of one type of the knock off product) should not be used for ANY Lead testing at all.
- Lead Safe Mama, LLC’s current choice for Lead-paint testing (for homeowners/ tenants, etc.) is the Scitus brand product (Scitus is the original, USA-made product that Chinese companies “knocked off” to make the above pictured product).
I have written this piece because parents everywhere have (for more than three years now) been contacting me in a panic — because something they bought for their children (something they were certain was Lead-free), has allegedly “tested ‘positive’ for Lead” with the knock-off swabs (swabs which they chose to purchase simply because they were the less expensive option on Amazon,)
To learn more about using the Scitus-brand kits, watch this video.
Important points to note:
- False Positives: These off-brand home test kits for Lead (which are marketed for testing consumer goods even though they do not work for that purpose) give false positives on many, many substrates, including several different types of metal substrates like (specifically but not limited to) Zinc — and possibly also Copper.
- Because of the frequency of false-positives, these off-brand kits have zero reliability for testing consumer goods — especially (again) given the widespread panic and misinformation spread on social media (including in parenting groups and on parenting-related pages) that seems to accompany many of the false positives found. Some specific examples:
- Parents tested a crane toy with one of these tests — link — and thought it was positive for unsafe Levels of Lead, when in fact it has zero Lead in any components.
- Another example is the Kyte Baby sleep sack fiasco that unfolded on TikTok in February of 2023 (the original videos were taken down once the creator realized the test kit was faulty, but some of the quotes from that video can still be found)!
- We also frequently see posts on social media in which the poster suggests that these swabs tested positive simply from touching WATER or white PAPER!
- One Common “False Positive” Scenario: If a painted item has a Zinc substrate, such as a zipper coated with Titanium Dioxide-based paint — as many zippers are — using one of these tests might result in a false positive from the exposed Zinc substrate on that item (areas of the zipper where the paint has chipped). So the consumer doing the testing may wrongly assume that the surface paint of the item tested is positive for unsafe levels of Lead (this is what happened with the Kyte Baby sleep sack zipper testing).
- False Negatives: These home test kits also often result in false negatives on many consumer goods — including dishes and vintage toys.
- This is the case with all reactive agent home test kits (for most consumer goods). These test kits were simply not designed to test consumer goods.
- False negatives can happen when the item being tested is positive for Lead, but positive for Lead at a level below the 500 ppm low-threshold of detection of the home test kit.
- False negatives can also happen when the chemical agent does not react with certain substrates (base-materials) even though the substrate is positive for Lead. We have seen this happen with Leaded-brass, high-fire ceramics and Lead-contaminated plastics.
- Within the realm of “False Negative” considerations – even if these kits DO work to detect the presence (or absence) of Lead, they are not testing for other toxic heavy metals (Arsenic, Cadmium, Antimony and Mercury – for example), so even though items tested may legitimately test negative for Lead with a home test kit, that does not automatically mean the item is safe.
- Designed for use with PAINT: Reactive-agent Lead-testing technology was designed to be used for/ is only meant to be used for testing for Lead in House Paint (to determine if the paint on homes is Lead-based paint).
- Again, these kits were not designed to test consumer goods.
- Their use should be restricted to testing house paint for Lead.
- The off-brand / knock-off (non-Scitus-brands) products should not be used under any circumstances.
- “Better Than Nothing?” Some Lead Safe Mama readers have asked, “But aren’t these home test kits better than nothing — for testing consumer goods?”
- My answer to this is: these tests are decidedly not better than nothing for testing consumer goods, given that the false positives AND false negatives are causing too much panic and misinformation among the people who use the kits … and the people who follow those people on social media! (The false information can spread very quickly, causing quite a bit of unwarranted alarm, and also potentially damaging companies who are actually producing Lead-free products that erroneously test positive with these faulty kits.)
- In response to the work of Lead Safe Mama, LLC, the company that manufactures the Scitus-brand kit worked on reformulating their products so that they work even better than they initially did.
- These kits have a low-threshold of detection of 500 parts per million (ppm), which is similar to the low threshold of detection of the discontinued 3M test kits.
- Lead Safe Mama, LLC helped Scitus re-work the language in their packaging and in their online marketing to make it more clear that these home test kits should only be used to test for Lead in paint.
Laura says
Thank you for the warning on these. I had used these around my house. It turned color on our door knobs. I was quite upset and replaced most of them. Then saw this post, bought the 3M tests and retested. The 3M ones did not change color at all. Sounds like this common problem false positives? Will make sure to use only 3M going forward.
Aya says
These tests contain sodium rhodizonate which reacts with many bivalent metals and forms various colored complexes. This is the same chemical the police often use to detect gunshot residue which has lead. [There are other tests for gunshot residue that detect nitrites. A paper by Feigl 1942 – Analytical Uses of Sodium Rhodizonate has a table of the various colors that may be obtained for different metals and how they change under neutral and acidic conditions. [I can send a copy if you’d like]. Often the variation in color in neutral vs acidic conditions will be helpful to distinguish between lead and Zinc. For example, these are expected to give brown-violet color when detecting zinc under neutral conditions (water) but no color under acidic conditions ( e.g. vinegar or HCl). Lead should test blue violet under neutral conditions and scarlet under acidic conditions. Cadmium should test brown red under all conditions. The colors are not easy to determine though because they look quite alike. And the testing of alloys becomes complicated. I tested something with a strong suspicion for lead and it turned blue-violet even with vinegar.
Interestingly, while wetting one of these the water dripped onto a bowl which quickly turned bright pink so I was convinced the crockery had lead. But plastic tupperware also tested positive and so did a glass jar. While it is possible that all of them have lead, it is quite unlikely. (I haven’t tested the Ikea plates that you showed had no lead, that will be interesting). Our water should not have lead as we had the lead pipes removed and our water has high mineral content – when the plumbers showed us the old lead pipes they were so thickly coated by calcium carbonate (?) that the pipe hole had halved. Then I sprayed the pink water with vinegar and the color completely disappeared instead of becoming scarlet or more intense indicating it was not lead in the first place. The reason why the color would become more intense is because Pb becomes more reactive in an acidic solution (ions).
While I do agree that these could create panic, people outside of the US do not have access to 3M tests and 3M tests are also designed only for paint. And pretty much nobody has access to an XRF instrument. I wish I could post the table here but happy to provide it so you can post it in case people continue using them for lack of any other options.
It did show that the paint in my room did not have lead (painted a couple of years before the UK banned lead paint but likely at a time when it was already being phased out). It did not show lead in older paint in an 100 year old house but I only swabbed around cracks and did not grind the paint etc. so it’s very possible that user error gave a false negative.
Tamara, thank you for the wonderful work that you do! I have learned a lot from you.
Aya
Tamara says
Thank you for sharing this! Please do email me the table: TamaraRubin@mac.com
Morgan in Austin says
Thanks for these details. My lead test swabs left a yellow residue (i.e. negative) in the collection dish, which turned alarmingly magenta with the addition of tap water. Following your hint I acidified with vinegar and the magenta immediately reverted to yellow, so I guess we have zinc
Carla says
can you tell me if the French White Corningware round casserole dishes prior to year 2000 have lead? and the Thomas train roundhouse set with various cars prior to 2003 have lead? I bought it to keep my 2 year old busy while pregnant! Wash hoping to keep for grandchild.
Courtney says
Would these work for testing for lead in paint in a house? The 3M tests seem to be sold out everywhere.
Tiffany says
3m seems to be having a huge shortage of their tests. What are your thoughts on these? Pro-Lab Lead Surface Test Kit
PRO-LAB Lead Surface Do It Yourself DIY Test Kit LS104 https://amzn.to/442qmX1
Tamara says
These are not at all accurate (to my knowledge) – especially not down to 5 ppm Lead.
t
Justyna says
Hello, I am very nervous because by chance (crawling with my baby) I spotted remainings of white paint on my reclaimed wood (old mill) table, underneath it. I tested it with the kit you don’t recommend (trying to get hold off the 3M). In two places the (white) paint turned pink. Would you still think there’s fair chance it is a false positive? Thank you very much.
Jean says
Hello. I just reviewed the technical report on the 3M Lead Check test kits and was surprised to see that the false positive rate for a non-technical user is 98 percent. (P 23) . Even a technical operator gets 75% false positives. There is a table later in the report that appears to show that even of the lead level is zeeo, the test will come out positive 40% of the time. Am. Understanding this correctly and what are your thoughts about the high false positive rate? https://www.epa.gov/sites/default/files/documents/3M-leadcheck-report.pdf
Tamara says
That is fundamentally industry-influenced propaganda. It is a subject I need to break down and discuss in detail. The “propaganda” stems primarily from the fact that they are considering positives for Lead levels above 600 ppm (but below 5,000 ppm) “false positives” when the test was actually originally designed to test for levels of 600 ppm and up (because the 1978 law limited lead in paint to 600 ppm.)
T
MJ Moscowitz says
Hello Lead Safe Mama!
is the “3M™ 8 Swab LeadCheck™ White, Red And Black Kit” accurate for testing ceramics and glassware? I am
cleaning out vintage glassware from my family home’s attic and wondering if a vintage tea set with a luster orange finish is safe to use. This kit is supposedly accurate for not only paint but ceramic.
Thank you!
sincerely,
MJ
Tamara says
Hello! They really are not accurate for most consumer goods -read this for context:
https://tamararubin.com/2017/02/ask-tamara-q-can-i-test-my-dishes-for-lead-with-a-leadcheck-swab-a-sometimes-but-not-always-click-to-read-more/
Tamara
MJ says
Thank you for the info
Andrea says
I didn’t buy these I bought for Amazon another brand as the 3M are discontinued now. Anyway I’m in the UK and hoping a galvanized magnetic board geared at kids is safe but feel like thats all it is hope
Allie edwards says
I really want to test antiques in my home. What can I buy to test consumer goods that isn’t a knock off? I’m concerned as my toddlers lead levels in her blood weren’t alarming, but present.
S says
What suggestions do you have for testing your own mugs and other things that aren’t paint? I’ve been searching everywhere and no luck.
Jo says
Hi there,
I’m looking into the faults of these Chinese tests after having been exposed through my life & have both my children exposed too. I would like a copy of the paper by Feigl 1942 – Analytical Uses of Sodium Rhodizonate.
Please please. Thank you so much.
Jo Elisabeth Edwards says
Hi Lead Safe Mama, Could you please send the Feigl paper as above , this would be so useful for some research I am doing & I cannot gain access to the report myself. Please.
Sweigh says
Hi. Thanks for this! I just used the Scitus test swabs on a 1950’s desk i got at Goodwill that I am thinking of refinishing. They turned brown, not red…the desk looks like it was shellacked, not painted, but might have some stain. I can’t tell if the brown is just shellac coming off on the swab, or a change of color indicating rust. I know you aren’t an expert, but in your experience with these test swabs, have you seen them turn brown and have that not be lead? Thanks!