To determine the prevalence of heat strain and factors associated with heat strain among workers at an aluminum smelter in Texas.
Continuous core body temperature (Tc), heart rate, and pre- and postshift serum electrolytes, and urine specific gravity were measured, and symptom questionnaires were administered.
Most participants (54%) had 1 or more signs of heat strain. Unacclimatized participants were significantly more likely to exceed the American Conference of Governmental Industrial Hygienists–recommended Tc than acclimatized participants (88% vs 20%; P < 0.01). Participants who exceeded the Tc for their acclimatization status and/or exceeded the recommended sustained peak HR had a significantly lower body mass index than those who did not (27.6 vs 31.8 and 28.4 vs 32.4, respectively; P = 0.01).
Employees and management need to strictly adhere to a heat stress management program to minimize heat stress and strain.