At a glance
| Chemical family | Diester of fumaric acid — biocidal anti-mould agent |
| CAS number | 624-49-7 |
| Classification | Not classified as a carcinogen by IARC. EU CLP Skin Sens. 1A (H317 — strongest sensitisation category), Acute Tox. 4, Eye Irrit. 2. Banned in EU consumer products (REACH Annex XVII Entry 61) |
| Where you encounter it | Historically placed in sachets inside leather furniture, shoes, and bags during ocean shipping to prevent mould growth. Now banned in the EU, US (via CPSIA), and most major markets |
| Sleep micro-environment relevance | Historically relevant — DMFu in furniture sachets caused thousands of cases of severe contact dermatitis. Now banned but legacy products may remain in circulation, particularly in less-regulated markets |
Regulatory & certification status
| European Union | Banned under REACH Annex XVII Entry 61: DMFu must not be used in consumer products or product parts at concentrations greater than 0.1 mg/kg. Originally emergency-banned by Commission Decision 2009/251/EC, made permanent in 2012. Regulatory — European Union authority |
| United States | Not specifically named in a federal ban, but products causing injury are subject to CPSIA and CPSC enforcement. FDA approved DMFu as an oral drug for multiple sclerosis (Tecfidera) at different doses — distinct from biocidal use. Regulatory |
| Canada | No specific DMFu product restriction, but covered under the Canada Consumer Product Safety Act general safety provisions. Regulatory |
| International | RAPEX (EU rapid alert system) issued numerous notifications during 2007-2009. OEKO-TEX Standard 100 does not allow DMFu. The incident led to strengthening of the EU General Product Safety Directive. Regulatory |
What it is
Dimethyl fumarate is a simple diester of fumaric acid, used as a biocide to prevent mould growth on leather and textile products during long-distance shipping (particularly from Asia to Europe). The problem emerged because DMFu was not applied to the products themselves — it was placed in small sachets inside the furniture or shoes. During shipping, DMFu vapours permeated the materials. When consumers sat on these sofas or wore these shoes, the DMFu caused severe allergic contact dermatitis, with symptoms including painful erythema, chemical burns, blistering, and respiratory difficulty. Some cases required hospitalisation. The epidemic was traced primarily to sofas manufactured in China and sold through European retailers. DMFu is not a carcinogen — its toxicity is immunological (severe skin sensitisation).
Where it shows up in bedding
DMFu was used in furniture — sofas, armchairs, and shoes — not typically in mattresses or bedding. However, the mechanism is directly relevant to the bedroom: a biocidal chemical placed inside a product during shipping that the consumer was never told about, causing harm through skin contact during normal use. The ‘toxic sofa’ incident is one of the clearest cases of undisclosed furniture chemicals causing widespread consumer harm. The lessons shaped EU product safety regulation and raised awareness of chemical exposure from furniture in the home. If you own leather furniture purchased before 2012 from unknown sources, and it causes unexplained skin reactions, DMFu exposure is worth considering.
Citations
- EU Commission Decision 2009/251/EC requiring Member States to ban DMFu in consumer products. Source Regulatory
- ECHA. REACH Annex XVII Entry 61 — Dimethyl fumarate restriction. Source Regulatory
- Rantanen, T. (2008). The cause of the Chinese sofa/chair dermatitis epidemic is likely to be contact allergy to dimethyl fumarate, a novel potent contact sensitizer. British Journal of Dermatology, 159(1): 218-220. Source Peer-reviewed
Frequently asked questions
What was the toxic sofa epidemic?
Between 2006 and 2009, thousands of consumers in Europe (primarily the UK, France, Finland, and Sweden) suffered severe contact dermatitis from new sofas and chairs. The cause was traced to small sachets of dimethyl fumarate (DMFu) placed inside the furniture during manufacture and shipping to prevent mould. DMFu vapours permeated the leather and fabric, and consumers developed painful burns, blisters, and persistent rashes from sitting on the furniture. The EU emergency-banned DMFu in 2009.
Could my furniture still contain DMFu?
If your leather furniture was purchased before 2012 in the EU (or before awareness reached other markets), and was manufactured in Southeast Asia without clear chemical disclosure, it could theoretically contain DMFu residue. The EU ban set a limit of 0.1 mg/kg. Products manufactured after 2012 under EU-regulated supply chains should not contain DMFu. If older leather furniture causes unexplained skin reactions, DMFu is worth considering as a cause.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-07-07. If you find a factual error, contact us.