Liquid laboratory waste containing osmic acid and cacodylic acid was mixed with potter's clay or hydraulic cement. The clay-waste product was kneaded into blocks and baked in a klin (1,200-1,400 degrees C). The cement-waste product was allowed to harden into concrete blocks. Some of the baked clay blocks and concrete blocks were ground, and immersed in 1 N NaOH or 10% HCI solutions for 3-6 months. X-ray microanalysis of the dried samples of these solutions showed that no leakage of osmium and arsenic occurred in the baked clay embedding, and that some leakage of these agents occurred in the concrete embedding. The present study indicates that the baked clay embedding method is useful for safe storage of dangerous laboratory wastes. Additional experiments suggested that glass embedding is also useful for safe storage of laboratory wastes or harmful metals.</p
