Cal. Public Resources Code § 4446

Every person shall exercise reasonable care in the disposal of flammable material so that the material does not cause the inception of or spread of uncontrolled fire. A person shall not burn any flammable material in any incinerator within any state responsibility area, within any area receiving fire protection by the director by contract, or upon federal lands administered by the United States Department of Agriculture or Department of the Interior, unless all of the following minimum requirements are complied with: (a) The area within 10 feet of the exterior of the incinerator is maintained free and clear of all flammable material and vegetation. (b) A screen constructed of a nonflammable material, with no greater than14-inch mesh, or metal doors, close or cover each opening in the exterior of an incinerator to prevent the escape of flames, sparks, ashes, or other burning material which might cause an uncontrolled fire. (c) A permit is obtained prior to burning for the use of the incinerator pursuant to Section 4423 and all other applicable provisions of law. This section does not apply to the disposal of flammable material incident to the processing of forest products.