Designed to protect in work areas where electric arc or flash fires can occur, the Carhartt Carhartt Flame-Resistant Twill Work Pant is made with a 9 oz. FR blend of 88% cotton, 12% high-tenacity nylon. This pant sits slightly below the natural waist with a full seat and thigh for a comfortable fit all day. The front is a zipper fly with Nomex® FR tape and an acr-resistant button closure at the waist. Carhartt has equipped this FR Twill Work pant with two reinforced back pockets for convenient storage and leg openings that fit over work boots. NFPA 70E and 2122 compliant with the following ratings, HRC: 2, ATPV: 12.4.