Weak organic odour from entrained flotation reagents a dark grey, heavy, soil-like material that is not flammable or combustible under normal conditions of transport and storage. However, when heated strongly in air it will burn, releasing toxic and irritating sulphur dioxide gas as well as possible lead and zinc oxide fumes. Contact with strong acids will generate flammable and highly toxic hydrogen sulphide gas (h2s). Inhalation or ingestion of concentrate dust may produce both acute and chronic health effects. Possible cancer hazard due to lead, cadmium and silica content. Possible reproductive hazard due to lead content. Scba and full protective clothing required for fire emergency response personnel.