I just looked up in the Merck catalogue of chemical supplies and the LD 50 oral for Brenzcatechin is 360 mg/kg body weight, Pyrogallol is 760 mg/kg. In the Swiss rating for poisons Brenzcathine is rated as more toxic (class 2) than Pyro (class 3), in the German rating both are classified as Harmful, which is one class below toxic. For comparison hydrochinon, harmful, LD50 oral 320mg/kg, Swiss class 3. LD 50: lethal dosis 50% of test species dies(posted 8510 days ago)Referring DiXactol bath B, I ran some experiments with two bath dev. based on catechine, so bath B needs strong alkali plus some anti-fog to reduce base-fog otherwise your filmbase will be toned as well, try 0.5-1 g KBr/ 100 ml stock solution
Regards,
Wolfram