At a glance
| Chemical family | Dithiocarbamate — rubber vulcanization accelerator and fungicide (trade name Thiram) |
| CAS number | 137-26-8 |
| Classification | IARC Group 3 (not classifiable as to carcinogenicity, Monographs Vol. 53, 1991). EU CLP Acute Tox. 4, Skin Sens. 1 (H317), STOT RE 2, Aquatic Acute 1 / Chronic 1. Also used as a fungicide under the trade name Thiram |
| Where you encounter it | Latex gloves; natural rubber latex mattress components; elastic waistbands; shoe soles and insoles; tire rubber; also used as a fungicide (Thiram) on seeds and crops |
| Sleep micro-environment relevance | One of the most potent rubber contact allergens. Present in elastic and rubber components of bedding and sleepwear. The primary concern is allergic contact dermatitis during prolonged skin contact overnight |
Regulatory & certification status
| European Union | REACH registered substance. CLP Skin Sens. 1 (H317), Acute Tox. 4, STOT RE 2, Aquatic Acute 1 / Chronic 1. Thiram fungicide use under review for EU re-approval under the Plant Protection Products Regulation (not approved since 2019). Regulatory |
| United States | EPA-registered fungicide (Thiram). No consumer product restriction for rubber use. Included in standard dermatological patch test series. Regulatory |
| Canada | PMRA-registered fungicide. No specific consumer product rubber restriction. Regulatory |
| International | IARC Group 3 (Monographs Vol. 53, 1991). Part of the standard patch test series worldwide. EU fungicide approval expired 2019 — under re-evaluation. Regulatory |
What it is
Thiuram (TMTD, tetramethylthiuram disulfide) is a member of the dithiocarbamate family used as a rubber vulcanization accelerator and as an agricultural fungicide (marketed under the trade name Thiram). It was first used in rubber processing in the 1920s and remains one of the most important rubber chemicals globally. IARC evaluated TMTD in 1991 and classified it as Group 3 — there was limited evidence of carcinogenicity in humans and inadequate evidence in animals. The primary health concern is contact allergy: the thiuram mix (comprising tetramethylthiuram disulfide, tetramethylthiuram monosulfide, tetraethylthiuram disulfide, and dipentamethylene thiuram disulfide) is one of the most commonly positive patch test panels in dermatology clinics worldwide.
Where it shows up in bedding
Thiuram is present in the bedroom through rubber and elastic components: natural latex mattresses and toppers, elastic waistbands on pyjamas and underwear, rubber feet and gaskets on bed frames, and the elastic in fitted sheets. Latex gloves worn for skin protection at night (for hand eczema) are, ironically, a common source of thiuram exposure. For sensitised individuals, prolonged overnight contact with thiuram-containing elastic or rubber causes dermatitis at the contact sites. The pattern of dermatitis — at waistband lines, at areas contacting elastic — often provides the diagnostic clue. Thiuram-free rubber alternatives exist and are used in hypoallergenic gloves.
Citations
- IARC (1991). Thiram. IARC Monographs Vol. 53. Source Peer-reviewed
- Cashman, M.W. et al. (2012). Contact Dermatitis in the United States. Dermatitis, 23(6): 241-244. Source Peer-reviewed
- ECHA. Tetramethylthiuram disulfide — Substance Information. Source Regulatory
Frequently asked questions
How do I know if I'm allergic to thiuram?
Thiuram allergy is diagnosed by a dermatologist through patch testing — small amounts of the thiuram mix are applied to the skin under occlusion for 48 hours, and the site is read for an allergic reaction. If you experience unexplained eczema at elastic waistband lines, at areas where rubber contacts your skin during sleep, or from wearing rubber gloves, ask your dermatologist to include the rubber accelerator series in your patch test.
Can I use a latex mattress if I'm allergic to thiuram?
It depends. Natural latex mattresses contain vulcanised rubber that may contain thiuram or its related compounds. If you have a confirmed thiuram allergy, the safest option is a synthetic foam mattress (polyurethane or memory foam) that does not contain rubber chemicals. If you prefer latex for its sleep properties, a thick mattress encasement that prevents direct skin-to-rubber contact may be sufficient, but this should be discussed with your dermatologist.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-07-08. If you find a factual error, contact us.