Hluav taws kub qhov rooj tub ntxhais yog ib tiam tshiab ntawm cov khoom siv hluav taws xob tsis muaj hluav taws kub. Feem ntau yog ntuj magnesium oxychloride inorganic ib puag ncig tiv thaiv cov ntaub ntawv. Lub qhov rooj hluav taws kub yog tsis-flammable thiab tsis tawg, tiv taus dej, roj, tshuaj corrosion, tsis muaj tshuaj lom thiab muaj zog txhua yam.