One retail unit of a 40% zinc oxide diaper rash paste was analysed by an independent laboratory at a consumer advocate’s request. Lead was 1401.0 ppb and cadmium 509.5 ppb as received. Arsenic and mercury were below the reporting values. The cadmium result is the highest of the four single-product laboratory reports in this collection.
Key numbers
The laboratory report (Purity Laboratories, Inc.; case 2508194; received 08/14/2025, tested and completed 08/20/2025) was issued for a sample labelled “Diaper Rash Paste Lot# 2025-169”. The advocate’s annotation identifies it as a 40% zinc oxide skin-protectant diaper rash paste.
| Analyte | Result (ppb, as received) | Note |
|---|---|---|
| Arsenic | < 10.00 | below reporting value; not speciated |
| Cadmium | 509.5 | detected |
| Lead | 1401.0 | detected |
| Mercury | < 5.00 | below reporting value; not speciated |
The article describes the lead level as “significantly over 1,000 ppb (40% over)”, which matches 1401.0 against 1,000 ppb. It calls the result “the third highest level of Lead we have found in a diaper rash ointment to date”. On the posting date (19 September 2025) that was true of the author’s July and August reports. Later reports on the author’s comparison chart changed the ranking.
Methods (brief)
ICP-MS. No sample mass, digestion, calibration, recovery, detection limit or accreditation is printed. Results apply to the sample as received, so the basis is the finished product as sold. Arsenic and mercury are totals.
Evidence fitness
The report supports a single-lot, as-received concentration of total lead and total cadmium in one 40% zinc oxide paste. It does not support a distribution, a comparison across brands or lots, an absorbed dose, or a regulatory conclusion.
Limitations
This is one sample with no published quality control. The article compares the result with the Washington State 1 ppm cosmetic lead limit and also says the state agency may decline to act on products sold with medical properties. The statute is not in this collection. Zinc oxide diaper-rash products are regulated in the United States as over-the-counter skin-protectant drugs.
Related evidence
- Diaper Cream, ZnO-Based
- Consumer-advocacy comparison chart of lead, cadmium, mercury and arsenic in eleven diaper creams (updated January 2026)
- Lead
- Cadmium
Update history
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