Sodium hexametaphosphate (SHMP) is generally recognized as safe (GRAS) by regulatory agencies, such as the U.S. Food and Drug Administration (FDA), for specific uses. However, its safety depends on the context and amount of use:

Common Uses and Safety

1. Food Additive: SHMP is often used in small quantities as a food additive (E452i) for emulsification, stabilization, and moisture retention. It is considered safe when used within the limits set by food safety guidelines.

2. Water Treatment: It is used to prevent scale formation and corrosion in water treatment processes. In this application, it is not intended for direct consumption, but the treated water must meet regulatory safety standards.

3. Industrial Applications: SHMP is also used in detergents, ceramics, and paper manufacturing. These applications typically do not involve direct human contact or consumption.

Potential Risks

1. Excessive Consumption: Overconsumption of SHMP in food can disrupt calcium-phosphorus balance in the body, potentially affecting bone health over time.

2. Skin or Eye Irritation: Prolonged or direct exposure to SHMP in its raw form may cause irritation to the skin, eyes, or respiratory tract.

3. Environmental Concerns: In large quantities, phosphates can contribute to water eutrophication, which negatively impacts aquatic ecosystems.

Precautions

• Always adhere to recommended concentrations and use guidelines.

• Avoid inhaling dust or allowing prolonged skin contact during handling.

• Ensure treated water or food meets safety regulations for phosphate content.