The phrase "to chemicals" is an idiomatic expression that means to undergo a chemical reaction or change. It can also be used figuratively to describe a change in behavior or personality.
Usage examples
Avoid exposure to chemicals: Always wear protective gear such as gloves and goggles when working with chemicals to minimize any potential harm.
There are tens of thousands of chemicals in use today and more than a forth of these are known to be toxic and nothing is known about their interactive effects. (naturopathicwellness.com)
Changing when light occurred changed the production of chemicals in other types of produce, too, including blueberries and zucchini. (sciencenewsforstudents.org)
It's one thing to make a case on paper that we can implement a 5,000 - line - long set of chemical reactions with DNA. (discovermagazine.com)