•Incorporation of silica reduces flammability of viscose fibres.•Wash permanency can be improved by formation of aluminium silicate.•Dyeability of aluminosilicate modified fibres remains unchanged.•Silica residues remain during combustion and act as a barrier for oxygen.•Incorporation of silica forms a green approach to flame retardant textiles. Safety requirements led to widespread use of textile products with reduced flammability. The global production of nearly 3 million tons of flame retardants generates a substantial environmental burden both during synthesis of the chemicals and disposal of waste textiles. In this work a cleaner technology to impart reduced flammability to viscose fibres is presented, which bases on the incorporation of 20%wt of silica into the cellulose fibre matrix during the stage of fibre formation. Stabilisation of the silica against unwanted leaching during washing procedures was achieved by treatment with aluminate, which reacts with silica under formation of the less soluble aluminosilicate. This treatment successfully was combined with the reactive dyeing step where no precipitation of dyes, losses in colour depth or reduced fastness of the dyeings occurred. Substantial reduction in time of afterglowing (-82%) and in length of destroyed material (-90%) were observed in standard tests for ignitability of bedclothes. The incorporation of silica into regenerated cellulose fibres offers a green alternative to the rather polluting finishing processes used today. The use of these modified fibres is of particular value for textile products worn next to the skin, as leaching of irritating flame retardants to the skin can be avoided. Display omitted