Here’s what Tom’s of Maine Toothpastes and Deodorants has to say:

Tom’s of Maine uses Propylene Glycol

“Propylene glycol is considered a safe and appropriate ingredient not just for cosmetic products, but also for ingested products like food and pharmaceuticals. It is on the US Food and Drug Administration’s list of ingredients which are Generally Recognized As Safe (GRAS) and is recognized by the World Health Organization as safe for use. There have been claims made that propylene glycol is an inappropriate ingredient for cosmetics and foods because it can also be used in products (such as antifreeze) which one would not want to consume. Such observations are well-intended but not very informative. The American Society for the Prevention of Cruelty to Animals (ASPCA) actually recommends the use of propylene glycol-based antifreeze because it is safer than ethylene glycol should pets accidentally ingest it.”

Tom’s goes on to say:

“For the record, the MSDS for the propylene glycol we use contains no indications of carcinogenicity or chronic exposure effects. We feel confident that research and a long history of safe usage have shown propylene glycol to be a safe and appropriate ingredient…”