NAGOYA - A construction site in Nagoya has introduced an AI-based system that analyzes workers’ facial expressions to assess heatstroke risk in real time.
On May 21st, temperatures in Hida, Gifu Prefecture, soared to 35.0°C, marking the first "extremely hot day" of the season anywhere in Japan and signaling an early onset of midsummer-like conditions. The intense heat swept across central Japan, with Nagoya recording a high of 31.2°C for the second day in a row, while Matsusaka in Mie Prefecture reached 31.3°C. As residents took to the streets in short sleeves and opened sun umbrellas under unexpectedly strong sunshine, concerns over heat-related illness quickly mounted.
In Toyota City, Aichi Prefecture, the dangers of this sudden heat became tragically clear on May 20th. An elderly man in his 80s collapsed while working inside a vinyl greenhouse. Discovered by a family member in a dazed state, he was rushed to a hospital in cardiac arrest but was later confirmed dead. Authorities suspect heatstroke as the cause. The case underscored how even early-season heat can overwhelm those not yet acclimated, especially when working in enclosed, high-temperature environments.
As these risks come into sharper focus, efforts are accelerating to prevent workplace heatstroke, particularly in high-risk sectors like construction. At a large high-rise building site in Nagoya’s Naka Ward, approximately 200 skilled workers received a direct appeal from Aichi Labor Bureau officials on the morning of May 21st. "Although July and August are typically the most dangerous months for heatstroke, cases are already occurring in May, when the body has not yet adjusted to the heat," warned Kobayashi, head of the bureau. Her remarks reflect a growing sense of urgency among labor authorities, who are seeing a notable rise in occupational heatstroke cases.
Last year, Aichi Prefecture recorded 88 workers who suffered from heatstroke severe enough to force absences of four or more days, an increase of 28 from the previous year. A disproportionate number of those cases were reported in the construction industry, where long hours under the sun and physical exertion create particularly hazardous conditions. In response, the Ministry of Health, Labor and Welfare has amended the Industrial Safety and Health Regulations to mandate heatstroke prevention measures beginning in June. The revised rules will apply to worksites where the Wet Bulb Globe Temperature (WBGT)—a composite measure of heat, humidity, and radiation—reaches 28°C or higher, or where air temperatures exceed 31°C for more than an hour. Employers failing to take adequate precautions may face penalties.
In anticipation of these changes, the Nagoya construction site has already adopted a range of preventive strategies. One notable measure is an artificial intelligence system that analyzes facial expressions to detect signs of heat distress before symptoms worsen. The site has also established a dedicated cooling station equipped with air conditioning where workers can rest and recover. Kobayashi emphasized that awareness and vigilance are growing among employers, noting that the rule revisions are aimed at preventing severe outcomes by ensuring safety protocols are in place across all relevant worksites.
Source: Nagoya TV News
