PDFWAC 16-228-1440
What pesticides must be artificially colored or have an odor added?
(1) No highly toxic pesticide in powdered or granular form or highly toxic pesticide baits having a label recommendation for use in any building, ship, or similar enclosure shall be sold within the state of Washington unless it is distinctly colored or discolored in such a way that it does not resemble any food.
(2) A pesticide in liquid form with colors resembling a beverage or liquid food, which does not have a distinctive odor, shall have an odorous substance added that is distinctly different from any beverage or liquid food.