Section 704.106  Classification of Injection Wells

Injection wells are classified as follows:

a)         Class I Injection Wells.  Any of the following is a Class I injection well:

1)         A well used by a generator of hazardous waste or the owner or operator of a hazardous waste management facility to inject hazardous waste beneath the lowermost formation containing a USDW within 402 meters (one-quarter mile) of the well bore.

2)         Any other industrial and municipal disposal well that injects fluids beneath the lowermost formation containing a USDW within 402 meters (one-quarter mile) of the well bore.

3)         A radioactive waste disposal well that injects fluids below the lowermost formation containing a USDW within 402 meters (one-quarter mile) of the well bore.

b)         Class II Injection Wells.  Any well that injects any of the following fluids is a Class II injection well:

1)         Fluids that are brought to the surface in connection with natural gas storage operations, or conventional oil or natural gas production, and which may be commingled with waste waters from gas plants that are an integral part of production operations, unless those waters are classified as a hazardous waste at the time of injection;

2)         Fluids injected for enhanced recovery of oil or natural gas; and

3)         Fluids injected for storage of hydrocarbons that are liquid at standard temperature and pressure.

c)         Class III Injection Wells.  Any well that injects fluids for the extraction of minerals, including the following:

1)         The mining of sulfur by the Frasch process;

2)         The in-situ production of uranium or other metals. This category includes only in-situ production from ore bodies that have not been conventionally mined.  Solution mining of conventional mines, such as stopes leaching, is included as a Class V injection well; and

3)         Solution mining of salts or potash.

d)         Class IV Injection Wells.  Any of the following is a Class IV injection well:

1)         A well used by a generator of hazardous waste or of radioactive waste, by the owner or operator of a hazardous waste management facility or by the owner or operator of a radioactive waste disposal site to dispose of hazardous wastes or radioactive wastes into a formation that contains a USDW within 402 meters (one-quarter mile) of the well.

2)         A well used by a generator of hazardous waste or of radioactive waste, by the owner or operator of a hazardous waste management facility, or by the owner or operator of a radioactive waste disposal site to dispose of hazardous waste or radioactive waste above a formation that contains a USDW within 402 meters (one-quarter mile) of the well.

3)         A well used by a generator of hazardous waste or the owner or operator of a hazardous waste management facility to dispose of hazardous waste that cannot be classified under any of subsections (a)(1), (d)(1), or (d)(2) (e.g., a well that is used to dispose of hazardous waste into or above a formation that contains an aquifer that has been exempted pursuant to 35 Ill. Adm. Code 730.104).

e)         Class V Injection Wells.  Any injection well that is not classified as a Class I, II, III, IV, or VI injection well.  Section 704.281 describes specific types of Class V injection wells.

f)         Class VI Injection Wells.

1)         An injection well that is not experimental in nature which is used for geologic sequestration of carbon dioxide beneath the lowermost formation containing a USDW;

2)         An injection well that is used for geologic sequestration of carbon dioxide which has been granted a permit that includes alternative injection well depth requirements pursuant to Section 730.195; or

3)         An injection well that is used for geologic sequestration of carbon dioxide which has received an expansion to the areal extent of an existing Class II enhanced oil recovery or enhanced gas recovery aquifer exemption pursuant to Section 704.123(d) and 35 Ill. Adm. Code 730.104.

BOARD NOTE: Derived from 40 CFR 144.6 (2017).

(Source:  Amended at 42 Ill. Reg. 21095, effective November 19, 2018)