Household ingredient · Contaminant
1,4-Dioxane
- CAS
- 123-91-1
A manufacturing by-product of ethoxylated surfactants rather than an added ingredient. Classified by IARC as possibly carcinogenic (Group 2B) and listed under California Proposition 65.
- Expert review pending
Concern level
A regulatory warning or restriction somewhere, or strong evidence of harm at typical intake. The concern level sets how many points 1,4-Dioxane costs on a product’s receipt.
What the evidence says
-
IARC Group 2B (possibly carcinogenic)Strong evidence
IARC classifies 1,4-dioxane as Group 2B (possibly carcinogenic to humans). [1]
-
Warning label requiredRegulatory
Listed under California Proposition 65 (cancer, 1988). [2]
-
May contain 1,4-dioxaneStrong evidence
It forms as a by-product when ingredients are ethoxylated. [3]
Evidence tiers say how sure the evidence is, separately from how much it matters. About evidence tiers.
Rules around the world
| Where | Status | Details | Date | Source |
|---|---|---|---|---|
| California (US) | Warning label required | Proposition 65 listing (cancer), 1988. | Jan 1, 1988 | [2] |
“Banned” means explicitly prohibited or withdrawn after review; “not permitted” means never authorized there. We use each regulator’s own words.
Names GoodSwap recognizes on labels (4)
- dioxane
- p dioxane
- 1 4 dioxane
- 1 4 diethylene dioxide
Sources
-
Agents Classified by the IARC Monographs, Volumes 1–142 (List of Classifications)
monographs.iarc.who.int
-
Proposition 65 List of Chemicals Known to the State to Cause Cancer or Reproductive Toxicity
“The date refers to the initial appearance of the chemical on the list.”
oehha.ca.gov
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1,4-Dioxane in Cosmetics: A Manufacturing Byproduct
“1,4-dioxane forms as a byproduct during the manufacturing process of certain cosmetic ingredients.”
fda.gov