AbstractA series of cellulose–polysilicic acid hybrid fibres with 15–35% silica contents were spun and their flammabilities were assessed by the LOI oxygen index test. Also, the rate of heat release and toxicities of fumes evolved during the combustion process for hybrid fibre with 33% SiO2loading was obtained using the cone calorimeter and FT‐IR techniques. The low flammability and toxicity indices indicate that this hybrid fibre can be used as a flame‐retardan