Work-related accidents in the U.S. happen more often when the temperature rises above 90 degrees Fahrenheit, according to a recent study from the Workers' Compensation Research Institute (WCRI). The probability of injuries at work jumps 5% to 6% on hotter days, with construction workers in the American South at the greatest risk, the study said. The WCRI said there are direct and indirect work-related injuries caused by heat. Direct heat injuries are physiological and lead to such symptoms as heat exhaustion, syncope and cramps, while indirect injuries occur when heat impairs the perceptual, motor or cognitive abilities of workers leading to falls. Related: Can the gig economy boom without benefits? Just this week, the National Integrated Heat Health Information System (NIHHIS) reported that more than 70 million people in the U.S. are under extreme heat alerts, with portions of Indiana, Ohio and Michigan were under excessive heat warnings. "It is important to note that workers can adapt, or acclimatize to excessive heat, which could reduce the incidence of heat-related work accidents," the WCRI said in the report.

How to mitigate heat-related illness and injury

The Occupational Safety and Health Administration (OSHA) recommends employers develop a heat illness-prevention program to ensure workplace safety during scalding days. This may require employers to conduct routine workplace inspections to identify and address heat hazards before an employee becomes ill or injured. The slideshow above illustrates the elements of an effective heat illness-prevention program, according to OSHA.