Mordants and Safety

The more I read up about dyeing yarn, the more I'm curious about the chemistry behind the dyeing process.

Mordants and Safety (Note: all safety information was obtained from www.sigmaalderich.com)

• Alum (potassium aluminium sulfate) - do not breathe dust, avoid contact with skin and eyes. MSDS information says that it is an irritant.
  
• Chrome (potassium dichromate) - Dangerous for the environment, very toxic, oxidizing. Sigma recommends use of Eye-shields, Gloves and reusable respirators to protect yourself. Under health risks - may be fatal if inhaled. (Note: many items dealt with in the lab are toxic and dangerous to work with. I must admit that I do not read the potential harms for each chemical I use. But I have to say, the more I read about potassium dichromate, the less I would ever want to use it in my home!) This is not something that you can just toss down the drain or in your trashcan after use, but apparently you can re-use the mordant solution.
  
• copper (copper sulfate) - do not breathe dust, avoid contact with skin and eyes. MSDS information says that it is an irritant.
  
• Iron (ferrous sulfate) - Same as copper sulfate.
  
• tin (stannous chloride) - Corrosive, very harmful if inhaled, can cause irritation.
  

The article "Are mordants safe?" suggests that many of the salts (except for chrome) are not really that bad since we requre all in trace amounts to survive. (Ingesting some tin when you consume food out of a can is different from eating something cooked in trace stannous chloride residue.) I would never EVER eat out of something that I used for lab work, and I would not recommend ever using items used for mordant for food either.

I am not an expert on dyeing. But the comments on this post are my opinions based on how I deal with lab equipment.