News

I refer to the article, “Extra cover from the sizzling afternoon sun” (April 14), which was accompanied by a photo showing two construction workers wearing helmets with pieces of cardboard attached as makeshift shields to protect them from the afternoon sun.   The seemingly innocuous photo raises the question of whether we are doing enough to protect workers who work long hours in the heat.  Thermal hazards are an important consideration in occupational health and safety. Heat stress occurs when the body accumulates more heat than it can remove. While a wet-bulb globe temperature of 35 deg C is thought to be the extreme heat limit, studies suggest that uncompensated heat stress can occur in young, healthy adults at temperatures significantly lower than 35 deg C in humid environments. A wet-bulb globe temperature is a measurement of how heat affects the body, taking into account factors like humidity, wind and cloud cover. Some studies suggest a threshold of 27 to 30 deg C – which Singapore’s ambient temperatures often exceed – for heat-related illnesses such as heat exhaustion and heat stroke. Should the individual be poorly acclimatised or have existing medical conditions, this threshold may be lower.  Although the workers in the picture may have used the cardboard pieces as a quick fix, it is not ideal. The Workplace Safety and Health Council’s guidelines for employers on managing heat stress in the workplace set up a hierarchy of controls.  Engineering controls to reduce heat accumulation must be actively sought, such as increasing ventilation, cooling or misting fans, reflective shields, or the use of sheltered mechanical equipment to perform tasks. A nearby tent with cooled benches can also be set up for rest breaks.  Modifying work practices, through mandated rest breaks in a cooler environment, scheduling work at cooler times of the day like late afternoon, rotating job functions, and regular hydration with cool fluids are pivotal. Regular monitoring of the wet-bulb globe temperature is also crucial to assess the risk of heat stress. Knowing workers’ limits is essential; their fitness to work should be assessed and they must first be acclimatised. Workers should also be trained to recognise heat stress and initiate emergency response measures appropriately, since timely intervention can prevent life-threatening heat-related illness.