At a glance
| Chemical family | Transition metal — most common metal contact allergen |
| CAS number | 7440-02-0 |
| Classification | IARC Group 1 (nickel compounds, inhalation — carcinogenic to humans); IARC Group 2B (metallic nickel — possibly carcinogenic); EU Skin Sens. 1 (H317) |
| Where you encounter it | Mattress springs, metal bed frames, zippers, snaps, grommets, belt buckles, jewellery; stainless steel alloys; coins; some pigments |
| Sleep micro-environment relevance | Contact allergy from nickel-releasing metal hardware in mattresses, bed frames, and bedding components. The carcinogenic risk is occupational (inhalation) and does not apply to consumer skin contact |
Regulatory & certification status
| European Union | REACH Annex XVII Entry 27 restricts nickel release to 0.5 µg/cm²/week from articles in prolonged skin contact (post assemblies, zippers, snaps, rivets, etc.). CLP Skin Sens. 1 (H317), Carc. 2 (H351) for metallic nickel. Regulatory — European Union authority |
| United States | No federal restriction on nickel in consumer products (unlike the EU). California Proposition 65 listed (cancer — nickel compounds). OSHA occupational exposure limits for nickel. Regulatory |
| Canada | No specific consumer-product nickel release limit (unlike EU). CEPA Schedule 1 for some nickel compounds. Regulatory |
| International | IARC Group 1 (nickel compounds, inhalation) / Group 2B (metallic nickel). OEKO-TEX Standard 100 limits extractable nickel in textiles. EU Toy Safety Directive restricts nickel release in toys. Regulatory |
What it is
Nickel is a silvery transition metal widely used in alloys (stainless steel, nickel-plated metals) and in many everyday objects. IARC classified nickel compounds as Group 1 (carcinogenic to humans) in 1990, based on evidence of lung and nasal sinus cancers in nickel refinery workers exposed to inhaled nickel dust and fumes. Metallic nickel was classified as Group 2B (possibly carcinogenic). The carcinogenic risk is from occupational inhalation, not from skin contact with nickel-containing objects. However, nickel is the most prevalent metal contact allergen globally — nickel allergy (allergic contact dermatitis) is extremely common, particularly in women, driven by prolonged skin contact with nickel-releasing metals in jewellery, clothing hardware, and household objects.
Where it shows up in bedding
Nickel is present in multiple bedroom components: innerspring mattress coils (steel alloy), metal bed frames and headboards, zippers on mattress covers, decorative snaps and grommets on bedding, and any metal hardware in adjustable bases. For people with nickel allergy, prolonged skin contact with nickel-releasing metal parts during sleep can trigger allergic contact dermatitis — redness, itching, and eczema at contact sites. The EU restricts nickel release from articles in prolonged skin contact under REACH Annex XVII Entry 27.
Citations
- IARC (1990). Chromium, Nickel and Welding. IARC Monographs Vol. 49. Source Peer-reviewed
- ATSDR (2005). Toxicological Profile for Nickel. Agency for Toxic Substances and Disease Registry. Source Regulatory
- EU REACH Annex XVII Entry 27 — Nickel release restriction. Source Regulatory
Frequently asked questions
Does nickel in mattress springs cause cancer?
No. The carcinogenic risk from nickel is specifically from inhaling nickel refinery dust in occupational settings — not from skin contact with nickel-containing metal objects. IARC Group 1 applies to nickel compounds via inhalation. The steel alloys used in mattress springs release negligible amounts of nickel and do not create inhalable dust under normal use.
Can mattress hardware trigger nickel allergy?
Yes. Nickel allergy is the most common metal allergy worldwide, and prolonged skin contact with nickel-releasing metal parts in mattresses (zippers, snaps, grommets) or bed frames can trigger allergic contact dermatitis. If you have a diagnosed nickel allergy, look for nickel-free hardware or use a mattress protector that prevents direct skin contact with metal components.
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.