Walk-in freezers are a common feature in restaurants, laboratories and industrial plants. They make it easier to store larger quantities of items than other types of freezers, such as reach-in freezers, can hold. Walk-in freezers range in size from 117 to as much as 1,022 cubic feet. Cooler-rooms and freezers are not intended to be workplaces, so they present unique hazards.
Workers and other personnel are liable to get trapped in a walk-in freezer if the door shuts accidentally behind them. Internal door releases often become frozen with the subzero temperatures and impossible to pry open. While walk-in freezers are required by law to come equipped with emergency release mechanisms, panic buttons, light switches and other safety items, even a few minutes of unprotected exposure to the temperature can cause frostbite and even hypothermia.
Exposure to Refrigerants
Refrigerants are chemicals, typically in liquid form, that function as cooling agents. They are used extensively in refrigerators, freezers and coolers to maintain a constant level of subzero temperature. Some of the most popular freezer refrigerants include chloroform, carbon tetrachloride, methyl chloride, methyl fluoride, dichloroethane and propane. According to Roy J. Dossat in the book "Principles of Refrigeration," all refrigerants are toxic in large quantities and create oxygen deficiency. Some cause problems in small concentrations, while others cause harmful effects in larger concentrations, including cardiac sensitisation and anesthetic effects. Some refrigerants, including ethylene, ethane, butane and isobutane are highly combustible.
A walk-in freezer is a confined space and a hazardous environment. According to the University of Minnesota, oxygen deficiency is the most common cause of death in confined spaces. Factors such as improper ventilation systems and the excessive release of refrigerant gases due to a leak or other reasons displace oxygen and result in a build-up of toxic fumes. An oxygen content that is less than 19.5 per cent by volume is considered an atmospheric hazard and hinders the body's ability to function normally. Symptoms of oxygen deficiency include a feeling of uneasiness, body weakness, memory loss, decreased immunity, fatigue, dizziness, depression and poor digestion. Oxygen deficiency also causes cellular and tissue death, leading to brain death and suffocation.