"Chemical treatment" means any product or procedure, including the preparation or application of the product, that alters or changes the molecular structure of the hair, skin, or nails through the use of chemicals. Chemical treatments include, but are not limited to the following:

1. (a) Permanent waving and soft permanent waving;
2. (b) Chemical straightening; and
3. (c) Hair coloring and lightening, including semi-permanent, permanent, temporary, or demi permanent coloring.

Source. #14459, eff 1-1-26