Environmental groups in the US state of Texas have made repeated calls about the potential risks of injection wells to human health and the surrounding environment.

Based on the significant concerns expressed, the US Environmental Protection Agency (EPA) has agreed to review the state’s authority in Texas regarding licensing Class II injection wells.

There are about 180,000 injection wells in the United States, and Texas has the largest share of them, in addition to other states such as California, Kansas, and Oklahoma.

Injection wells are used to re-pump fluids associated with oil and natural gas production, which mainly consist of salt water and various chemicals below the surface of the earth.

These wells are also used to pump carbon dioxide underground to increase oil extraction rates from active fields.

Environmental groups point to frequent incidents of well blowouts and seismic activity in some areas of Texas, particularly in the Permian Basin, due to injection wells.