Abstract: A process for preparing a polyurethane foam that contains particles of expandable graphite and a halogenated fire-retardant additive which surprisingly impart excellent fire-retardant properties to the foam and provide a stable isocyanate-reactive component having improved pot life for industrial scale production purposes. The polyurethane foam can be prepared by mixing a single isocyanate-reactive component containing the graphite and halogenated additives along with all of the polyols and other ingredients with an isocyanate component in a two-component mixing machine such as a high-pressure mixing device for applying the reaction mixture into a suitable container.