development work began on an improved dual hazard dh blend i e a blend capable of producing fabric that can meet both nfpa 2112 flame resistance certification and nfpa 70e arc flash protection certification the initial focus was on a blend comprising 45 para aramid 45 tencel 10 nylon char length and thermal shrinkage were found not to be optimal so development continued a first blend was modified to include modacrylic 1 45 modacrylic 45 tencel 10 para aramid a second blend was also considered 2 40 modacrylic 40 tencel 20 para aramid the nylon in the earlier blends was replaced with para aramid to improve char length and thermal shrinkage there were encouraging results with these blends particularly blend 1 relative to the earlier blends that included higher percentages of fr fibers the inventors considered further increasing the percentage of non fr fibers particularly tencel although it was thought that increasing the percentage of non fr fibers above that of the fr modacrylic fibers would probably be counter productive to flame resistance nevertheless further development of blends with higher non fr content was conducted ultimately it was found that surprisingly a blend in accordance with the present invention having more non fr cellulosic content than modacrylic fr content achieved the sought after flame resistance as well as the desired arc resistance and also allowed the fabric to meet applicable requirements for thermal.