Propylene oxide derived glycol ethers: A review of the alkyl glycol ethers potential to cause endocrine disruption.

The 'propylene glycol ethers' (PGEs) are a group of chemical solvents and functional fluids produced through the reaction of propylene oxide (PO) and a monoalcohol. PGEs form different structural isomers, with possible permutations increasing with the number of PO units in the molecule. The dominant isomers have only secondary hydroxyl groups and are not able to be metabolized to the acid structures that are associated with reproductive toxicity. There have been published claims that glycol ethers are human endocrine disruptors. This review systematically evaluates all the available and relevant in vitro and in vivo data across the propylene glycol ether family of substances using an approach based around the EFSA/ECHA 2018 guidance for the identification of endocrine disruptors. The conclusion reached is that there is no evidence to show that PGEs target any endocrine organs or perturb endocrine pathways.