Canadian Occupational Safety (COS) magazine is the premier workplace health and safety publication in Canada. We cover a wide range of topics ranging from office to heavy industry, and from general safety management to specific workplace hazards.
Issue link: https://digital.thesafetymag.com/i/1262450
F E A T U R E 16 www.thesafetymag.com/ca HEAT STRESS: PLAYING IT COOL Extreme heat in the workplace can have severe health effects. Linda Johnson reports on the different kinds of PPE needed to keep workers safe from heat stress. A bakery worker at a Weston Bakeries facility in Barrie, Ont. was working at large ovens during a heat wave in August 2001. Fifteen minutes before the end of a 12-hour shift, the worker collapsed and died of heat stroke. At the time of his death, his core body temperature was 42.5 C. Every year, hundreds of workers in Canada suffer injuries due to heat- related causes. These injuries can have dire effects. Managers and workers should know what kinds of cooling personal protective equipment (PPE) are appropriate for their workplace. While PPE cannot be seen as the primary means of preventing injury caused by extreme heat, it is often an essential means to reduce the risk. Heat stress is an illness caused by a buildup of body heat that is produced by the environment (air temperature, humidity, air movement and hot sources or radiation from the sun) combined with the physical exertion of the work and the clothing and equipment workers are wearing. A rise in the body's temperature to several degrees above 37 C can cause serious and possibly fatal conditions. Seasonal workers and others who work outside in summer are among those most at risk of heat stress, says Kelly Fernandes, occupational hygienist at Mississauga, Ont.-based Workplace Safety and Prevention Services. These include agricultural, landscape, logging, forestry and construction workers. There are also many other people who work indoors and are exposed to radiant heat from hot surfaces or substances (such as molten metals) or process heat; for notice the signs and symptoms of heat exhaustion in themselves or others or if they realize they haven't had enough water — that should be a reminder to them: I'm starting to not feel well, and they should take action," Fernandes says. Preventive measures When the risk of excessive heat exposure has been identified in the workplace, then the employer, using the hierarchy of controls, should develop a heat stress program and take preventive measures. Risk of heat stress can be reduced by: • working out of direct sunlight; • providing hydration stations and ensuring workers drink water regularly; • controlling the exposure temperature (reduce radiant heat from machines); • providing regular rest breaks in shaded or air-conditioned areas; • working in teams; • rotating tasks; and • reducing workload. example, welders and metal fabricators and others who work in steel mills, foundries, mines, oil and gas facilities and bakeries. The health effects of heat stress include heat cramps and heat syncope, a feeling of dizziness or light- headedness. It may cause heat rash, which occurs when sweat ducts become blocked and sweat is trapped under the skin. The resulting inflammation produces symptoms such as small blisters, deep, red lumps and an intense itchy feeling. At the extreme end, a person can suffer heat stroke, which may cause confusion, disorientation, incoherence and vomiting. The skin is dry and red hot, and sweating has stopped. Heat stroke can lead to loss of consciousness, permanent injury or death. It is often preceded by heat exhaustion, with signs that include headache, nausea, dizziness, fatigue, extreme thirst, heavy sweating and irritability. "Workers and supervisors should be stopping that from happening. If they Before working in a very hot workplace, employers should ensure workers are acclimated to the heat, Fernandes says. Workers not used to working in high temperatures should have their exposure to heat and workload limited and then gradually increased before they are assigned regular hours and tasks. "You're building up their tolerance. Acclimation takes roughly seven to 14 days, but that depends on the worker. There are worker factors that can affect acclimation. If someone is older, that can be a factor in the acclimation process," she says. Workers and managers should be trained to recognize the symptoms of heat stress in themselves and their co-workers. They should understand the importance of regular hydration. The company should also be prepared to provide first aid quickly, have a communication system and have trained first responders. A heat stress assessment will, in addition to helping employers understand the heat stress risk in the workplace, help determine which preventive measures should be implemented and included in the company's heat stress program. When it is not possible to reduce the risk of heat stress to a safe level through engineering or administrative controls, for example, then cooling PPE should be used. Cooling PPE Generally, people working in hot conditions should wear garments made of cotton or other natural fibre, such as linen or silk. Outdoor workers "Workers and supervisors should be stopping [heat stress] from happening. If they notice the signs and symptoms of heat exhaustion in themselves or others… they should take action." Kelly Fernandes, occupational hygienist at Workplace Safety and Prevention Services