Phthalic anhydride is a solid that exists as white flakes. It has a musty odor. It occurs naturally, reportedly being present in baked potatoes. Though U.S. demand for phthalic anhydride has declined in recent years, it is likely to increase by 2 to 3 percent per year in the future. The largest users of phthalic anhydride are companies that make phthalate plasticizers, unsaturated polyesters, and alkyd resins.
Companies add phthalic anhydride to paints and rubber products.
They also use it to tan and cure leather products. Exposure to phthalic anhydride can occur in the workplace or in the environment following releases to air, water, land, or groundwater. Phthalic anhydride enters the body when people breathe air or consume water or food contaminated with phthalic anhydride. It can also be absorbed through skin contact. It does not remain in the body due to its breakdown and removal.