Section 30.640 - Waste Piles(1)310 CMR 30.640 through 30.649 prescribe requirements which apply to owners and operators of facilities that use waste piles to store or treat hazardous waste.(2) The containment of hazardous waste in a pile at the site of generation for any period of time is "storage" and not "accumulation" of hazardous waste and shall be subject to all the requirements of 310 CMR 30.640 through 30.649.(3)310 CMR 30.640 through 30.649 do not apply to owners or operators using waste piles that are closed with hazardous wastes left in place. Such waste piles are subject to regulation as landfills pursuant to 310 CMR 30.620.(4)310 CMR 30.641 and 30.660: Groundwater Protection do not apply to a waste pile that is inside or under a structure that provides protection from precipitation so that neither run-off nor leachate is generated, provided that:(a) Neither liquids nor materials containing free liquids are placed in the pile;(b) The pile is protected from surface water run-on by the structure or in some other manner acceptable to the Department;(c) Where necessary, the pile is designed and operated to control dispersal of the waste by wind by means other than wetting; and(d) The pile will not generate leachate through decomposition or any other reaction.