A flame-retardant composition has a plurality of particles with at least one porosity therein, a flame retardant gas occupying the porosity, and a matrix material in which said particles are dispersed. A sealant applied to at least a portion of the particles, wherein the sealant substantially prevents the gas from escaping the porosities. The matrix is a flame-retardant composition adapted to be applied to various surfaces. The matrix may also function as the sealant. The sealant is formed of a material that will break down and release the gas in the presence of water or flame or other selected conditions. The sealant may be a polymer material. This solves the problem of applying flame-retardant qualities to various surfaces.