The proper disposal of waste materials is covered under osha 1926.252 in

1962.252(a) whenever the material is dropped from 20feet to any poiny lying outside the exterior wall of building, an enclosed chute of wood, or equivalent material. For the purpose of paragraph, an enclose chute is a slide, closed in all sides, through which material is placed from high plac eto lower one. 1962.252(b) when the disposal is dropped through holes in the floor without the use of chute, the area onto which the material is dropped shall be completely enclosed with barricades not less than 42 inch high and not less than 6 feet back from the projected edge of of the opening valve. signs warning of hazards of falling material shall be posted at each level. 1962.252(c) All scrap lumper, waste material, and rubbish shall be removed from the immediate work area as the work progresses. 1962.252(d) Disposal of waste material or debris by burning shall comply with local fire regulation 1962.252(e) All sovent waste, oily rags, and flammable liquid should be kept in fire resistant covered container until removed from work site.