Flamecheck M-111 Fire Retardant Spray is easy to use and non-toxic. Flamecheck M-111 has been used by the movie industry when fire safety is of the utmost importance since 1989. Flamecheck M-111 can be used on fabric (natural, synthetic and blends), untreated wood, stage curtains, exhibition draperies/tablecloths, costumes, props, backdrops, Christmas trees, and many more absorbent surfaces. Calfire Reg#C-27001, Meets or exceeds NFPA 701-705, "Class A" ASTM E-84 on wood. When used on exterior absorbent surfaces, retreatment may be necessary. If possible, seal exterior surfaces with a fire-retardant finish, such as Flamecheck M-111PA (fire-retardant paint additive) or check annually depending on the amount of rainfall.