Calcium chloride is a common ionic compound and salt composed of calcium and chlorine. In its solid, anhydrous form, it is a white, odorless crystalline material that is highly soluble in water. The U.S. Food and Drug Administration (FDA) generally recognizes food-grade calcium chloride as safe (GRAS) for human consumption when used within specific limits. However, the concentrated material is classified as an irritant and can be corrosive, meaning its hazard potential depends almost entirely on its concentration and physical state.
Common Applications and Context
The average person encounters calcium chloride in a variety of common products and large-scale industrial uses. One widespread application is its use as a de-icing agent on roads and sidewalks, where it effectively lowers the freezing point of water to melt ice quickly. It is also employed as a dust suppressant on unpaved roads, binding fine particles together by attracting moisture from the air. In the home, it is a primary component in many salt-based dehumidifiers and desiccants, functioning to absorb excess moisture from damp spaces. Finally, it is widely used as a food additive (E509), acting as a firming agent in canned vegetables and in cheese-making, and sometimes as a low-sodium salt alternative.
Understanding the Primary Hazards
The hazard potential of concentrated calcium chloride stems from two chemical properties. First, it is strongly hygroscopic, meaning the solid material aggressively absorbs moisture from its surroundings. This intense water absorption, or desiccation, is the mechanism by which it dries out and irritates moist tissues. Second, when the solid compound dissolves in water, it undergoes an exothermic reaction, releasing a significant amount of heat. These two characteristics—water absorption and heat generation—are the root cause of its irritating and corrosive effects on the body.
Exposure Effects on the Human Body
Direct contact with concentrated calcium chloride primarily affects the skin, eyes, and mucous membranes. On the skin, its hygroscopic nature draws water out of the tissue, causing irritation, redness, and a sensation of dryness. Prolonged exposure can lead to chemical or thermal burns due to the substantial heat released when mixing with skin moisture. Eye exposure is particularly serious, causing severe irritation, pain, and potentially serious damage, including transient corneal injury.
Inhalation of dust from the powdered or granular form can irritate the upper respiratory tract, leading to a cough, sore throat, and a burning sensation. Ingestion of concentrated solid calcium chloride is highly dangerous because the exothermic reaction occurs immediately upon contact with the moist tissues of the mouth, throat, and esophagus. This rapid heat release can cause severe burns to the gastrointestinal tract, resulting in symptoms like vomiting, extreme thirst, and abdominal pain. Ingesting large amounts may also disrupt the body’s electrolyte balance, potentially leading to severe systemic issues, such as low blood pressure or cardiac disturbances.
Safe Handling and Emergency Response
Minimizing the risk of concentrated calcium chloride exposure requires proper handling, starting with storage in dry, airtight containers. This preventative measure is necessary to protect the product from moisture in the air, which would cause the material to clump and degrade. When working with the solid or highly concentrated forms, one should always wear personal protective equipment (PPE), including safety glasses or goggles, protective gloves, and an apron. Adequate ventilation is also important when handling the material to prevent the inhalation of dust.
In the event of skin contact, the affected area should be flushed immediately with copious amounts of water to wash away the material and dissipate any heat. For eye exposure, continuously rinsing the eyes with water for at least 15 minutes is a critical first step, and medical attention must be sought right away. If the material is ingested, do not attempt to induce vomiting; instead, the person should drink one or two glasses of water to dilute the chemical and then immediately seek emergency medical assistance.