Evaluation of heat stress and heat strain among employees working outdoors in an extremely hot environment.

A heat stress evaluation was conducted among employees engaged in strenuous work in an extremely hot outdoor environment. Environmental conditions that contribute to heat stress along with various physiological indicators of heat strain were monitored on a task-basis for nine employees daily across four workdays. Employees performed moderate to heavy tasks in elevated environmental conditions for longer periods of time than recommended by various heat stress exposure limits. Seven of nine employees showed evidence of excessive heat strain according to criteria yet all employees were able to self-regulate task duration and intensity to avoid heat-related illness.