Chapter 9: Solvents and hydrocarbons · Part 1: Glycol ethers
PnB
- Made from a hazardous chemical
The worst fact: it's moderately irritating to eyes and skin, and the OECD flagged that as a hazard users should know about. Australia classes it as "Causes skin irritation; Causes serious eye irritation".
Why brands use it: it lifts grease, couples water and oil, and evaporates at a controlled rate. Spray cleaners and wipes typically contain 0.5 to 2.5%, at most 4%; liquid hard-surface cleaners up to 6.7%.
Take care if: you get the neat product in your eyes.
Comes from: propylene oxide reacted with butanol. Australia classes propylene 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: "Propylene glycol ethers harm unborn babies like the ethylene ones": the evidence says no. The main form in commercial PnB (about 95%) can't be turned into the acids that cause those effects.
Contaminants: nil.
Fair to say: it isn't a skin allergen, and an industry risk assessment found household exposure over 300,000 times below the level of concern.
Correct as of November 2026. What the badges mean
Sources
- 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.
- OECD. SIDS initial assessment: propylene glycol ethers (SIAM 17, 2003).
- HERA. Propylene glycol n-butyl ether (2005); hydrotropes (2005).
The full source list is at the end of Chapter 9.