Staff Sgt. Aaron Devries, guest instructor from the 13th Battalion, 100th Regiment, discusses the 91J10 Quartermaster and Chemical Equipment Repairer Course on Jan. 9, 2026, at Regional Training Site-Maintenance at Fort McCoy, Wis. 91J (“Ninety-One Juliet”) is a U.S. Army military occupational specialty for Quartermaster and Chemical Equipment Repairer. Soldiers in this MOS are trained to perform maintenance, service, and repair on quartermaster gear and chemical equipment, including things like mobile water purification systems, laundry systems, heaters, decontamination units, and other special-purpose equipment. The coursework emphasizes reading technical manuals, using tools safely, and learning to troubleshoot and fix these...
