As the world grows hotter, the military grapples with a deadly enemy it can't kill

The medics loaded Sgt. Sylvester Cline into an ambulance with the air conditioning running at full blast. It was 4:20 p.m., 20 minutes after he’d been helped off a live-fire training range at Fort Chaffee in Arkansas, where it was 93 degrees and humid.

Cline, an Iraq combat veteran, and two other soldiers were being evacuated to a nearby barracks to rehydrate and cool off after nine hours of drills on parched training grounds on that sweltering day in June 2016.

Despite a forecast for extreme heat, base safety officers who prepared the daily risk assessment had decided soldiers faced only moderate danger. Later that morning, the temperature had reached 90 Fahrenheit, triggering “black flag” conditions, the military’s signal for a high risk of heat casualties. Commanders were supposed to allow at least 40 minutes rest for each hour of training, but they did not heed the requirement, an Army investigation found.

As the temperature climbed in the afternoon, reports went out of multiple soldiers falling ill in the heat, while requests to assess whether to halt the training were dismissed. Commanders refused to allow soldiers to shed heavy gear, and it took almost three hours for supply personnel to respond to field leaders’ urgent requests for ice, water and Gatorade, the military’s investigation reports show.