Section 27.03 - Classes of Injection Wells(1)Class I. (a) wells used by generators of hazardous wastes or owners or operators of hazardous waste management facilities to inject fluids beneath the lowermost formation containing a USDW within 1/4 mile of the well bore;(b) other industrial or municipal wells which inject fluids beneath the lowermost formation containing, within 1/4 mile of the well bore, an underground source of drinking water; and(c) radioactive waste disposal wells which inject fluids below the lowermost formation containing an underground source of drinking water within 1/4 mile of the well bore.(2)Class II. Wells used to inject fluids:(a) which are brought to the surface in connection with conventional oil or natural gas production and that may be commingled with wastewater from gas plants as an integral part of production operations, unless those waters are classified as hazardous waste at the time of injection;(b) for enhanced recovery of oil or natural gas; and(c) for storage of hydrocarbons that are liquid at standard temperature and pressure.(3)Class III. Wells used for extraction of minerals including:(a) mining of sulfur by the Frasch process;(b) solution mining of minerals;(c)in situ combustion of fossil fuel; and(d)in situ production of uranium or other metals. This category includes only in situ production from ore bodies which have not been conventionally mined. Solution mining of conventional mines (such as stopes leaching) is regulated as Class V.
(4)Class IV. Wells used by generators of hazardous or radioactive wastes, by owners or operators of hazardous waste management facilities, by owners or operators of radioactive waste disposal sites, or by any other person to dispose of hazardous wastes or radioactive wastes into or above a formation containing a USDW within 1/4 mile of the well bore.(5)Class V. Injection wells not included in Classes I, II, III, or IV. Class V injection wells are further defined in 310 CMR 27.05.Amended by Mass Register Issue 1322, eff. 9/23/2016.