All the fabrics used by Canary are washed in hot water and dried in machines where no detergent of any kind, or vinegar, or baking soda, is ever used. This is done before cutting and sewing to remove any finishes and ensure no shrinkage surprises.
For people with chemical sensitivites, there could be traces of finishing left in the fabric of a new Canary garment, which will come out with more washing or rinsing according to methods that work for you.
Since all Canary fabric is organic, the finishes are water-soluble and never contain formaldehyde or other chemicals and permanent resins. Check out the organic cotton posts for more on how organic processing is different from regular cottons.
My recommendation for everyone, sensitive or not, is to research and use non-toxic laundry soap and washing methods. Fabric softener of any kind is an unnecessary, and very harmful product everyone should avoid. Doing so benefits your health, the longevity of your clothes, and the environment.