Calcium chloride has a very low toxicity rating and is not dangerous to humans or the environment. It has been produced and used in a variety of industrial and food products for over a century. It is widely used as a de-icer on roads pavements driveways and parking lots because it is hygroscopic and produce more heat than sodium chloride when introduced to water. It is also used to help cure concrete faster like dust stabilizer in the production of plastics and calcium salt for efficient oil drilling sewage and water treatment as dessicant additive and in brine and food processing.
Because of its use in a wide range of substances especially food regular exposure to small amounts of calcium chloride are insignificant. The level and duration of exposure determine the severity of the result. The form of exposure could be as dust a solid in crystalline or reduced form or in liquid as it dissolves in water. As it is used in food and medicine it can also be consumed.
The biggest health hazard constituted by calcium chloride occurs when dissolved in water which large amounts of heat can be generated resulting in burns. To avoid this do not use hot water when dissolved calcium chloride. If inhaled causing dust irritation in the upper respiratory tract that can be solved by providing adequate ventilation. If small amounts are ingested they do not cause any problems. Ingestion of large amounts may cause irritation of mouth throat and stomach / intestines and can cause stomach problems and vomiting. Calcium chloride can also cause skin irritation and burns especially if water is present. In cases where a large amount is in contact with the skin it should be thoroughly rinsed with water.
Calcium chloride has been observed to cause browning of leaves on trees along the roads where it is used as a de-icer. Officials say the damage is minimal and the trees again during the summer but no formal studies have been conducted. It can also cause problems with disorientation in wild birds that ingest it when they peck for gravel on the roads. It is not considered to be toxic to fish and as it dissolves in water it is not considered a bio-accumulation hazard.
Although calcium is not very toxic people who work with it wear protective clothing and use precautions as recommended on the package. This may include gloves cover-alls and a respirator designed to filter properly particulates such as dust particles or liquid droplets. Dust on the floor can absorb moisture and become slippery so be sure to keep the area cleaned well.
Calcium chloride may produce toxic chlorine fumes when heated before it breaks down. It can also form hydrogen chloride when mixed with sulfuric or phosphoric acids. It can corrode certain metals over time such as steel aluminum and brass should so long-term storage options takes this into account.