After searching for a long time, I finally found an internet post from someone who had actually called the company and asked for a list of the ingredients. Here's an excerpt of that post:"I no longer would use or recommend Charlie's Soap as a 'natural' cleaner. Their active ingredient that they called butylcelosolv is Czech for 2-Butoxyethanol acetate, also known as Butyl Cellosolve. According to the [Environmental Working Group's] Skin Deep Database, which rates it a 5 (moderate hazard), butoxyethanol has ties to cancer, reproductive toxicity, neurotoxicity, and more. It's used in hundreds of cleaning products, even as an oil spill dispersant.... Charlie's Soap lists 2-butoxyethanol on its MSDS if there's any question."