Abstract: A composition is provided for detecting the presence of sulfur dioxide by changing color. One type of composition is prepared by mixing a small amount of finely ground potassium permanganate with finely powdered activated silica gel to produce a lilac colored material which will turn white in the presence of sulfur dioxide. Another type of composition is prepared by soaking silica gel in an aqueous solution of potassium permanganate to produce an amber colored material which will turn white in the presence of sulfur dioxide. Both types of detecting material can be combined with silicone rubber and molded into various shapes.