Thanks! I feel a lot better. Since I don't use Mike Ware's recipe, I'm not going to buy a respirator. I thought cyanotype was fairly safe since they make sun print kits for kids. I didn't know that in Germany, they used potassium ferricyanide as an anti-caking for salt. I'm sure it's safe because the E.U. standards for food safety is much higher than here in the US.