Published Jul 17, 2026, 3:00 AM EDT
The Marine Corps issued updated interim rules July 9 to help commanders prevent heat and cold stress injuries during training and operations.
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Published Jul 17, 2026, 3:00 AM EDT
During peak summer training and field exercises, heat stress injuries can pull Marines out of action faster than many expect. Cold-weather operations bring their own risks when units train or deploy in far-off northern lands or high terrain. The Marine Corps moved on July 9 to give commanders sharper tools to spot problems early and keep more Marines healthy. MARADMIN 311/26 replaces guidance last updated in 2015. It delivers interim direction on training, monitoring conditions with wet-bulb globe temperature (WBGT) equipment, and rapid response when someone shows signs of trouble. The message stays in effect until the details move into the main safety order, MCO 5100.29C. The update emphasizes risk management, documented training, local standing operating procedures, and clear reporting through the Risk Management Information system. Every commander and officer-in-charge now has explicit steps to reduce unnecessary injuries in both hot and cold environments.
