SW-401 Light Flux and SW-402 Dark Flux are bear a Non-Toxic label according to FDA standards. Note: Finishedware producers may be required to have their ware food safe tested prior to introducing into commerce. The Stoneware Flux’s are Dinnerware Safe when used according to manufacturer’s directions and fired to the clay body’s vitrification temperatures. However, discretion and judgment should be used if the glaze surface is heavily textured, less from a safety and more from an aesthetic perspective.