At a glance
| Chemical family | Organochlorine — pesticide and flame retardant (fully chlorinated cage structure) |
| CAS number | 2385-85-5 |
| Classification | IARC Group 2B (possibly carcinogenic to humans); Stockholm Convention Annex A (elimination); Canada SOR/2025-270 prohibited |
| Where you encounter it | Legacy environmental contaminant in household dust and food chain (fish, dairy); historically used as fire-ant insecticide and as flame retardant (Dechlorane) in plastics, rubber, electronics |
| Sleep micro-environment relevance | Not in any modern product — present as environmental persistence in dust and bioaccumulation in food. Extremely stable chemically; does not break down in indoor environments |
Regulatory & certification status
| European Union | POP Regulation (EU) 2019/1021 — banned (production, use, placing on market). One of the original 12 POPs listed under the Stockholm Convention. Regulatory |
| United States | EPA cancelled all pesticide registrations (1978). Listed as a hazardous substance under CERCLA. Not manufactured or imported. California Proposition 65 not explicitly listed (covered under broader categories). Regulatory |
| Canada | Prohibited under the Prohibition of Certain Toxic Substances Regulations, 2025 (SOR/2025-270), in force 30 June 2026 — manufacture, use, sale and import are banned. Regulatory — Canada authority |
| International | Stockholm Convention Annex A (elimination) — one of the original 'dirty dozen' POPs listed in 2004. IARC Group 2B (possibly carcinogenic). No exemptions remain. Regulatory — International authority |
What it is
Mirex is a cage-structured organochlorine with 12 chlorine atoms — one of the most chemically stable organic compounds ever manufactured. It was produced from the 1950s through the 1970s as an insecticide (primarily for imported fire ants in the US Southeast) and as a flame retardant under the trade name Dechlorane. It is distinct from Dechlorane Plus, which is a related but different compound also now listed under the Stockholm Convention. IARC classifies mirex as Group 2B based on sufficient evidence in animals and inadequate evidence in humans. Its extreme persistence and bioaccumulation led to its inclusion in the original 2004 Stockholm Convention 'dirty dozen.'
Where it shows up in bedding
Mirex is not and was never an ingredient in bedding products. Its relevance to the sleep environment is entirely through environmental persistence: mirex is detectable in household dust worldwide, especially in regions where it was applied (US Southeast fire-ant control, Great Lakes industrial contamination). It bioaccumulates through the food chain, so dietary exposure (particularly via fish and dairy) contributes to body burden. In the bedroom, dust ingestion and inhalation during sleep are secondary exposure pathways.
Citations
- IARC (1979). Mirex. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 20. Source Peer-reviewed
- Stockholm Convention. Listing of Mirex — Annex A (Elimination). Source Regulatory
- Government of Canada. Prohibition of Certain Toxic Substances Regulations, 2025 (SOR/2025-270). Source Regulatory
Frequently asked questions
Is mirex in any modern products?
No. Mirex has been banned globally since the Stockholm Convention entered into force in 2004, and production ceased in the late 1970s in most countries. No modern consumer product contains it intentionally. Its presence in the environment — including household dust — is entirely from historical contamination and its extreme chemical stability.
What is the difference between mirex and Dechlorane Plus?
Mirex was sold under the trade name 'Dechlorane' as a flame retardant. Dechlorane Plus is a structurally related but different compound (CAS 13560-89-9) that was developed as a replacement for mirex. Both are now listed under the Stockholm Convention, but they have different chemical structures, CAS numbers, and regulatory timelines. Dechlorane Plus was added to the Stockholm Convention in 2023, nearly two decades after mirex.
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.