Abstract: Sodium azide is used as a preservative or bacteriostatic agent of various solutions such as hypertonic phosphate solution, cleaning solutions used in electronic counting equipment, Sorensen's phosphate buffers, lytic agents E and F and the like. Unfortunately, sodium azide, when combined with lead or copper in sink plumbing can produce explosive substances and also is capable of generating toxic gases. By using sodium dehydroacetate with or without sodium borate decahydrate and/or disodium edetate, the disadvantages are removed and at the same time the efficiency of the various solutions is not affected adversely.