Chemophobia (yes, it's an actual term) is an irrational aversion to or prejudice against chemicals or chemistry. It's surprisingly common. And it's a surprisingly common argument against substances that some people don't like, or are prejudiced against.
You wouldn't believe how common it is for someone to warn people against using something because it contains "chemicals". Just that. Chemicals. As a concrete example, I saw someone on the YouTube comments of some video rallying people against using sunscreens because of all the "chemicals" that they contain. That was his only argument. The "chemicals".
If you have even the most basic understanding of what that word means, you would understand how completely ridiculous that argument is. Basically everything is a chemical. You consist almost completely of chemicals. Heck, water is a chemical. (A chemical is, essentially, a compound that contains more than one atom, which are bound to each other. Water being a good example.)
But somehow that word has become a boogeyman among many deluded people. Somehow "chemical" has become synonymous to something harmful, toxic and unhealthy, even though anything safe and healthy they could ever name also consists of chemicals. "Chemical" has somehow become a synonym for "artificially synthesized man-made compound (which is, of course, automatically hazardous to your health because it's unnatural)".
If you want to scare people about a substance, just tell then that it contains lots and lots of "chemicals". You aren't even lying by doing so, because basically all substances do indeed contain chemicals.