At a glance
| Chemical family | Alkaline earth metal — filler and pigment component |
| CAS number | 7440-39-3 |
| Classification | Not evaluated by IARC. Toxicity depends on chemical form — soluble barium compounds are toxic; barium sulfate is inert |
| Where you encounter it | Flame retardant back-coatings on textiles (as barium sulfate filler); white pigments (lithopone); household dust; drinking water |
| Sleep micro-environment relevance | Present in some flame retardant textile back-coatings as inert barium sulfate filler. Not a meaningful toxicological concern in bedding because the sulfate form is biologically inert |
Regulatory & certification status
| European Union | Not specifically restricted in textiles or consumer articles under REACH. Drinking water limit: 0.7 mg/L (WHO guideline value). Barium sulfate is exempt from most restrictions due to insolubility. Regulatory |
| United States | EPA MCL for barium in drinking water: 2.0 mg/L. No restriction on barium sulfate in consumer products. OSHA occupational limits for soluble barium compounds. Regulatory |
| Canada | Health Canada drinking water guideline: 2.0 mg/L barium. Regulatory |
| International | Not IARC classified. WHO drinking water guideline: 0.7 mg/L (revised 2004). Regulatory |
What it is
Barium is an alkaline earth metal that is never found free in nature — it always occurs as a compound. The toxicological significance of barium depends entirely on its chemical form. Barium sulfate (BaSO4) is extremely insoluble and biologically inert — it is used as a radiopaque contrast agent in medical imaging (barium swallow). Soluble barium compounds (barium chloride, barium carbonate) are toxic: they can cause hypokalemia, cardiac arrhythmias, respiratory failure, and gastrointestinal haemorrhage. IARC has not evaluated barium for carcinogenicity. In industry, barium sulfate is widely used as a filler in paints, plastics, rubber, and flame retardant coatings.
Where it shows up in bedding
Barium in the bedroom is primarily barium sulfate — an inert filler used in flame retardant back-coatings on textile fabrics, including some mattress ticking and curtain materials. Barium sulfate adds weight and improves the flame-barrier properties of back-coating formulations. Because barium sulfate is highly insoluble and biologically inert, it does not pose a toxicological risk in bedding applications. Trace barium can also be found in household dust from soil particles.
Citations
- ATSDR (2007). Toxicological Profile for Barium and Barium Compounds. Agency for Toxic Substances and Disease Registry. Source Regulatory
- WHO (2004). Barium in Drinking-water. Background Document for WHO Guidelines. Source Regulatory
- EPA. Barium — National Primary Drinking Water Regulations. Source Regulatory
Frequently asked questions
Is barium in mattresses dangerous?
In mattresses, barium is present almost exclusively as barium sulfate — an insoluble, biologically inert compound used as a filler in flame retardant back-coatings. This form of barium poses no toxicological risk. It is the same compound used safely in medical barium swallow imaging. Soluble barium compounds are toxic, but these are not used in bedding.
Why is barium used in flame retardant coatings?
Barium sulfate is used as an inert filler in flame retardant back-coating formulations for textiles. It adds mass to the coating (which improves flame-barrier performance), is chemically stable at high temperatures, and is non-toxic. It is one of the safer filler materials used in textile flame treatment.
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.