### Question
How is the "annular injection" defined?


### Answer
The term **annular injection** is defined in *42 U.S.C. § 300h* as follows -

> the reinjection of brines associated with the production of oil or gas between the production and surface casings of a conventional oil or gas producing well

#### Citation:
  - *42 U.S.C. § 300h*
  - Heading: **CHAPTER 6A-PUBLIC HEALTH SERVICE > SUBCHAPTER XII-SAFETY OF PUBLIC WATER SYSTEMS > Part C-Protection of Underground Sources of Drinking Water**

