Fortunately some of us use tubes for developing sheet film and there is no need to touch the stuff or for that matter work in the dark, hence avoiding any mishaps due to reduced vision. Better safe than sorry. In addition, buying Pyrocat in a liquid form kit, such as that available from Lotus View (I believe they are the only ones that provide this kind of service) , further reduces any chances of whatever miniscule, tiny, microscopic risk there might be of playing around with powdered chemicals.