I went to prochemicals website and got this info on Retayne, here is the link.
http://www.prochemical.com/MaterialSafety/Auxiliaries/2007%20Retayne.pdf
It seems pretty safe as long as you do not get the actual chemical in your eyes, mouth, or skin. It says it is not a known carcinogen, it does not enter through the skin or through inhalation. I would think it would be safe to use. Personally, I would rinse the fabric and dry it according to the bottles instructions to set the dye in the fabric and then I would probably wash it and rinse it again just to make sure all the chemical was out of the fabric.