The environmental impact of ID-11 or D76 is negligible. The powder kits sold by Kodak and Ilford are designed for domestic water waste treatment systems and for ordinary mortals to handle. Honestly unless you start guzzling it you're probably safe. Wear gloves if you think you might have skin allergies. Don't splash it in your eyes. Don't drink it.
Many things are "known to cause cancer in the state of California" which the entire rest of the world view as safe. But even stuff which are worldwide designated as various classes of carcinogen might be safe for consumption. Parsnips, for example. There's a big difference between class 1 carcinogen which effectively means take all precautions to eliminate consumption, inhalation and skin absorption of this stuff cos it's nasty....to class 3 carcinogen which more or less means "we fed mice on concentrated extracts of something in this and bathed their balls in it....and found slight evidence of cancer and genetic mutation".
though I don't specifically recommend this, when I was a child I used to develop positive paper in ID-11 and Bromophen using my mother's roasting trays. They're still in use some 40 years later and nobody seems to have suffered. Though I repeat, I specifically do not recommend using cookware actually used for cooking to mix or use photo chemicals.