Class IID Underground Injection Control Wells: What You Should Know

Russ Huffmyer, project manager with McKim & Creed, co-authored a fact sheet for the Marcellus Shale Coalition on Class II Underground Injection Control wells (UIC). The sheet defines Class II UIC wells, explains how fresh water aquifers are protected, and describes how oil and gas companies use injection wells.

Class IID UIC wells are deep wells (usually 2,000 to 8,000 feet deep) that are used to dispose of salt water and other fluids associated with oil and gas exploration and production. To isolate these waste fluids from drinking water aquifers, the wells require at least four layers of protective steel casing and cement. They are designed, constructed, permitted and operated in accordance with US EPA regulations (pursuant to the Safe Drinking Water Act). According to the fact sheet, “the EPA and state regulatory authorities identify underground injection as the most environmentally sound method for disposal of water generated from oil and gas well drilling, completions and production.”