Non-Flammable, Non-Toxic, Eco-Friendly formula. Aerosol propellant is nitrogen – no CFCs. Safe for food prep area. Bio Block® kills insects on contact with a 1 month residual activity. Bio Block® is available in either an aerosol or a 16 ounce pump spray. Independent tests prove that Bio Block® is as effective as the #1 indoor aerosol insecticide.