January 6, 2023
Updated: April 5, 2023 – Wednesday
There’s not much more to say about this. Do not buy these: https://amzn.to/3Zh0Dbc, or these (which are the Chinese knockoff of the product pictured): https://amzn.to/3ZczUwJ. Buying either of these is a total waste of money.
I have written this post because parents everywhere have (for more than two 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 these swabs (which they purchased on Amazon, because they were the less expensive option, compared to the 3M LeadCheck® test kits — the ”gold standard” for reactive-agent Lead-test kits .)
Important points to note:
- While – in response to the work of Lead Safe Mama, LLC – the company that manufactures the kit in the image above is currently (April 2023) working on reformulating these products so that they work better, with the product as currently formulated (for product available for purchase in April of 2023 and before) there is too much of an opportunity for user error, especially if the instructions — which can be found by using the QR code that comes with the product — are not very carefully followed.
- “Better Than Nothing”? Some Lead Safe Mama readers have asked “but aren’t they better than nothing?”
- My answer to this is that – as they are currently formulated – they are decidedly not better than nothing — 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! [And 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].
- False Positives: These home test kits for Lead 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 this, as currently formulated, they have zero reliability – 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.
- As an example: 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 of that video can still be found)!
- 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 will 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.
- Reactive-Agent testing has been designed to be used for / is only meant to be used for testing Lead in House Paint: As with the 3M LeadCheck® swabs, these reactive agent home test kits were initially designed for use on house paint (to determine if the paint on homes is Lead paint).
- Again, these kits were not designed to test consumer goods, and their use should be restricted to testing house paint for Lead.
At the moment, of the available choices on the market today, the only reactive agent test kits that work well and consistently are LeadCheck® swabs, and they are only good in certain applications they are specifically-designed for use only on paint — with a “high” low threshold of detection of 600 ppm — but may also work on some types of consumer goods). Please read this for context if you want to know when it might be appropriate to use LeadCheck® swabs.
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.
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.
Thank you for sharing this! Please do email me the table: TamaraRubin@mac.com
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.