Propionic acid, identified by CAS number 79-09-4, is a chemical that demands careful handling due to its inherent hazardous properties. It is classified as a flammable liquid and vapor, with a flash point of 54 °C (129 °F), meaning it can easily ignite when exposed to heat or open flames. Furthermore, it is highly corrosive, capable of causing severe skin burns and serious eye damage. Inhalation of its vapors can lead to respiratory irritation. Therefore, understanding and implementing the safety of propionic acid handling is paramount in any industrial or laboratory setting where it is used.

Personal protective equipment (PPE) is non-negotiable when working with propionic acid. This includes chemical-resistant gloves, eye protection such as safety goggles or a face shield, and protective clothing to prevent skin contact. Adequate ventilation is crucial to minimize inhalation exposure; working in fume hoods or well-ventilated areas is strongly recommended. Proper storage is also vital: containers should be tightly closed, kept away from heat and ignition sources, and stored in a cool, dry, well-ventilated area, away from incompatible materials.

Emergency procedures must be clearly defined and accessible. In case of skin contact, immediate flushing with plenty of water is necessary, followed by medical attention. For eye contact, thorough rinsing with water for at least 15 minutes, while ensuring eyelids are separated, is critical. Ingestion requires immediate medical attention. The chemical production of propionic acid and its various industrial uses, including its role as a food preservative and animal feed additive, all necessitate a robust safety culture. Even when considering biotechnological propionic acid synthesis, the end product's hazards remain the same. Adherence to Material Safety Data Sheets (MSDS) or Safety Data Sheets (SDS) for propionic acid is the fundamental step in ensuring safe operations.