A heat wave over much of the U.S. last week claimed a construction worker near Tucson—a stark reminder of the danger heat poses to those in the building trades. Mark Geise, 44, died of apparent heat-related illness while constructing a propane filling station at a Costco store. A resident of Indiana, Geise was employed by Seese Construction, Monrovia, Ind., according to his obituary.

The Marana Police Dept. and OSHA are investigating. It was the third heat-related death of an out-of-state resident in Tucson in the past month. After Geise collapsed at around 4:30 p.m., bystanders called 911 and began CPR. Arriving minutes later, paramedics began advanced life support on Geise but were unable to revive him, says Capt. Adam Goldberg of the Northwest Fire Rescue District.

According to witnesses, Geise became more fatigued throughout the day and was very thirsty; on the jobsite, temperatures reached 106˚ F. However, in the two hours prior to the 911 call, he couldn't keep water down due to dry heaves.

Goldberg says workers and supervisors should watch for symptoms and immediately hydrate and relocate the person into a cooler environment. When in doubt, call 911, he recommends.

Supervisors should keep a close eye on out-of-state workers and allow them to acclimatize by working for progressively longer periods in the heat, says Bruce Trethewy, communications manager with SCF Arizona, a Phoenix-based provider of worker's compensation insurance.

"Subcontractors throughout Arizona know heat is deadly," says Jim Kuliesh, president and CEO of the Alliance of Construction Trades in Tucson. "I've been here 17 years, and we've never had a heat-related death of our [members'] employees. They protect themselves."