340-044-0011 Classification of Underground Injection Systems Injection systems are classified as follows: (1) Class I. Injection systems that inject hazardous waste, radioactive waste or other fluids beneath the lowermost formation containing an underground source of drinking water. This includes the disposal of fluids containing hazardous waste or radioactive waste into wells, drill holes, sinkholes and cesspools regardless of their capacity or flow rate. (2) Class II. Injection systems that inject fluids: (a) Produced by natural gas storage operations, or conventional oil or natural gas production; (b) Used to enhance recovery of oil or natural gas; or (c) For storage of hydrocarbons that are liquid at standard temperature and pressure. (3) Class III. Injection systems that inject fluids for extraction of minerals or other natural resources including sulfur, uranium, metals, salts or potash by methods such as solution mining, in-situ production or stopes leaching. (4) Class IV. Injection systems that inject hazardous waste or radioactive waste into or above a formation containing an underground source of drinking water. This includes the disposal of fluids containing hazardous waste or radioactive waste into septic systems, drill holes and cesspools regardless of their capacity or flow rate. (5) Class V. Injection systems not included in Classes I, II, III or IV that inject fluids other than hazardous waste or radioactive waste into the subsurface. Types of Class V injection systems include, but are not limited to, the following: (a) Sanitary waste injection systems that inject sanitary waste fluids into subsurface fluid distribution or injection systems such as septic systems, drainfields, disposal trenches, seepage pits, cesspools, or sewage drain holes or drill holes. (b) Industrial/commercial injection systems that inject waste fluids from industrial or commercial business activities. Typical North American Industry Classification System (NAICS) industrial sectors that may produce waste fluids include manufacturing, agriculture, mining and transportation. Injection systems that combine or mix any amount of industrial or commercial wastewater or animal waste with storm water or sanitary waste are considered industrial/commercial injection systems. (c) Fluid return injection systems that re-inject spent geothermal fluids into the source aquifer following extraction of heat energy or electric power generation, spent brines after extraction of salts, or non-contact heat pump and air conditioning return fluids. Irrigation return flows are not considered fluid return flows. (d) Storm water injection systems that inject only storm water runoff from residential, commercial or industrial facilities or roadways. (e) Groundwater management injection systems that inject fluids to manage groundwater quality, groundwater levels, groundwater flow, or groundwater quantity. Injection systems may be used for aquifer recharge, aquifer storage and recovery, subsidence control, saltwater intrusion control, aquifer remediation, aquifer characterization, water well maintenance, groundwater table management, landslide stabilization or special experimental purposes. In general, fluids being injected have water quality equivalent to the background groundwater, or have only localized effects around the well bore when used in aquifer remediation or water well maintenance, or are beneficial to the aquifer remediation. Statutory/Other Authority: ORS 454.625, 468.020, 468B.020 & 468B.165 Statutes/Other Implemented: ORS 454.655, 468B.025, 468B.050, 468B.053 & 468B.160 History: DEQ 8-2001, f. 7-13-01, cert. ef. 9-20-01