Sodium tripolyphosphate (STPP) is a white, odorless component found in your laundry detergent. Its mineral composition softens hard water and enhances soap lather. It is a culinary ingredient that preserves fish wet and plump (but its safety is uncertain). STPP has an extensive range of industrial applications, including water treatment and paint pigment dispersal. Although it is normally harmless, over use of it might raise environmental issues.