Here's some dyeing info from Carol Soderlund
Posted on Thursday - July 21, 2005
Carol Soderlund is an expert dyer who has been teaching dyeing classes for a long time and has dyed fabric under many conditions. A reader of the quiltart list asked her opinion on dyeing outside and pouring the dye down a sink to a septic tank. Here is her answer, posted with her permission:
Procion MX dyes are not toxic, though you want to wear a mask while mixing powders because we can't wash out our lungs! The pH is not much higher than your usual load of laundry. It is not harmful to your septic system, though it is better to skip processes that involve salt. It won't hurt the grass or plants.
If dyeing outdoors, I would cover stuff you don't want colorful with plastic, and cover the dyed cloth with plastic while it batches. Do it on a warm day, and you'll have a great time!
Happy dyeing, Carol
Here is Carol's website: www.carolsoderlund.com