All developing chemistry should be handled with good chemical safety practices in place. Skin protection (I use nitrile gloves) is essential. Chemical dust and vapor is hazardous and thus must not be inhaled. Respirators or vented chemical hoods may be required for some mixing processes. Safety glasses may also be required.
Pyrogallol (1,2,3-Trihydroxybenzene), Hydroquinone(1,4-dihydroxybenzene) and Pyrocatechol (1,2-dihydroxybenzene) are very closely related benzene ring developing reagents. They are all toxic. In low (or no) sulfite solutions, they are all capable of staining the image and proportionally tanning the emulsion gelatin.
All of these reagents are used in both film and paper developing formulations. A very familiar formulation is Kodak Dektol (Metol/Hydroquinone).
I (and others) have been testing Donald Miller's PPPD (Pyrogallol, Pyrocatechol, Phenidone Developer) paper developing formulation.
43 gm Sodium Sulfite
.3 gm Phenidone
10 gm Pyrocatechol
5 gm Pyrogallol
50 gm Sodium Carbonate
3.5 gm Potassium Bromide
Water to make 1 liter
Dilute 1-1 to make 2 liter of use solution
The phenidone should be dissolved in alcohol just as in the Pyrocat formula
As in all cases where exposure to Pyrogallol is involved, eye protection, nitrile gloves, and respirator should be worn. (Just as in any pyro formulation).
I am looking for alternatives to Amidol for developing Azo contact prints. Search APUG for PPPD and Amidol.