I did want to add that mixing dyes outdoors or in a well ventilated studio space is the best idea. I had a professor in college that said that it was dangerous even to dye in your own kitchen because there is a risk that left out food or cooking/prep areas could become contaminated. Thank you for writing this post, it is really informative.

Yes, the commercial dye powders do carry labels saying “handle with care” but they are still generally considered safe to use by home dyers when also following their safety guidelines. For instance, my container of Lanaset dye powder carries a label that says “Warning: Product contained herein is industrial strength which must be handled with caution. Avoid contact with skin and eyes. Use in well ventilated area. To reduce exposure, use MESA-NIOSH approved respirator and gloves”. Arts and crafts supplies that are labelled “non-toxic” are not considered safe to eat.

All of the references I listed above relate to chemical dyeing and not so much to natural dyeing. However, some mordants used in natural dyeing are heavy metals and considered toxic or poisonous (e.g. chrome, tin, copper or iron in high concentrations). Alum is recommended as the safest mordant to use in natural dyeing.

My point here is just that yes, dyeing can be fun and creative but it has to be done with safety in mind. Here are two more links that will be useful: one about what dyes are safe/unsafe to use and another about safety in natural dyeing:

http://www.pburch.net/dyeing/FAQ/unsafedyes.shtml
http://www.pburch.net/dyeing/FAQ/naturalsafety.shtml