The invention relates to a biodegradable halogen-free flame retardants composition used for fire-safety and prevention, that limits and extinguishes fires by means of increased resistance to ignition, slowing down burning rates and the rate of heat, smoke and toxic gas release from polymers with different physical and chemical properties and structure, such as textiles, wooden materials, paper, cardboard, corrugated board, leather, cellular polystyrene, foamed polyurethane, and items made of them. The composition according to the invention contains orthophosphoric acid, urea, triethanolamine, ammonia water, polydimethylsiloxane, surfactant, which may be anionic, cationic, amphoteric, non-ionic or mixtures thereof and water.