Chapter 9: Solvents and hydrocarbons · Part 1: Glycol ethers
2-Butoxyethanol
- Made from a hazardous chemical
- Contaminant risk
The worst fact: in one reported poisoning, an adult who deliberately swallowed 250 to 500 mL of a window cleaner containing 12% 2-butoxyethanol fell into a deep coma, with acid building up in the blood and, days later, blood breakdown products in the urine. It passes through skin, even as vapour: in 1996 Australia's regulator estimated about 20% of what a person absorbs from the vapour comes through the skin. One early study under exaggerated conditions put it at 75%, but a later repeat found no more than 21%.
Why brands use it: it dissolves grease, mixes with water, and evaporates without streaking.
Take care if: you spray it, heat it, or have it on your skin for long. Australia classes it as "Harmful if swallowed; Harmful in contact with skin; Causes skin irritation; Causes serious eye irritation; Toxic if inhaled; Harmful if inhaled; May cause respiratory irritation". It's a Schedule 6 Poison above 10%. In 1996, Australia's regulator found most of 434 cleaning products had under 10%. Some glass cleaners went up to 40%, but those were mainly commercial products, and it found the risk from household products minimal because most contain low levels. For workplaces, it recommended switching from spraying to applying it as a liquid stream. In controlled studies, people had eye and airway irritation at 113 ppm.
Comes from: ethylene oxide reacted with butanol. Australia classes ethylene oxide as "May cause genetic defects; May cause cancer". That doesn't mean it's in the product, but it's not a great starting point for something you clean with.
Myth check: "It's a reproductive toxin like the other glycol ethers": not shown. Australia's regulator found the fertility and birth effects of its smaller cousins haven't been demonstrated with 2-butoxyethanol, apart from doses that were severely toxic to the adult animals.
Contaminants: other glycol ethers, butanol and ethylene glycol, which commercial grades may contain (no amounts published). They're unlikely in a well-made product, but it's a factor you can't see on the label.
Fair to say: in a US poison centre study, all 24 children who swallowed 5 to 300 mL of glass cleaner containing 0.5 to 9.9% had no symptoms. Rats are far more sensitive to its blood effects than people, and the WHO cancer agency rates it "not classifiable" as a human carcinogen.
Correct as of November 2026. What the badges mean
Sources
- Australian Government. Poisons Standard October 2026 (SUSMP), F2026L01327: 2-butoxyethanol; diethylene glycol monobutyl ether; hydrocarbons, liquid; toluene; xylene; tetrachloroethylene; trichloroethylene; Appendix B.
- Safe Work Australia. Hazardous Chemical Information System (HCIS): classifications for each chemical, and for ethylene oxide, propylene oxide, epichlorohydrin, benzene, 1,3-butadiene-containing butane and 1,2-dichloroethane. Workplace exposure standards (amended November 2025) and workplace exposure limits (July 2025). Labelling of workplace hazardous chemicals code of practice (2015). Trichloroethylene health monitoring guide.
- NICNAS. Priority Existing Chemical Reports No. 6: 2-butoxyethanol in cleaning products (1996); No. 8: trichloroethylene (2000); No. 15: tetrachloroethylene (2001). IMAP Tier II assessments: diethylene glycol monobutyl ether (2013); toluene (2017); xylenes (2019).
- US EPA. Trichloroethylene; regulation under TSCA, 89 FR 102568 (2024), and later notices (2025–2026); Perchloroethylene; regulation under TSCA, 89 FR 103560 (2024), and 91 FR 47145 (2026); 40 CFR 751.305 and 751.605; Carbon tetrachloride rule (2024); IRIS: ethylene glycol monobutyl ether (2010); Safer Choice Ingredient List.
- ATSDR. ToxFAQs: 2-butoxyethanol; propylene glycol; toluene; xylenes.
- IARC. Monographs vol. 88 (2-butoxyethanol), vol. 106 (trichloroethylene, tetrachloroethylene); Supplement 7 (mineral oils).
- HSDB (US National Library of Medicine), via PubChem: manufacturing, use and impurity data.
- Dean BS, Krenzelok EP. Clinical evaluation of pediatric ingestion of glass cleaners. J Toxicol Clin Toxicol 1992;30:557-563.
- Gualtieri JF et al. Repeated ingestion of 2-butoxyethanol. J Toxicol Clin Toxicol 2003;41:57-62.
The full source list is at the end of Chapter 9.