Unconventional oil and gas development produces billions of tons of waste annually. Waste products from shale gas operations include:
- Liquid waste such as brine and flowback water
- Sludges and semi-solids like tank bottoms
- Concentrated TENORM (technologically-enhanced naturally occurring radioactive material)
- Filter cake, filter socks, and material residues
- Solid waste such as drill cuttings
Unconventional oil and gas development requires extraordinary quantities of water during the extraction process. In 2019, drilling operators used an average of 14 million gallons of water per fracking event. Some hydrofracturing jobs required up to 39 million gallons for a single well. After it is pumped underground to “frack” oil and gas wells, water that initially returns to the surface is called “flowback,” and includes naturally-occurring underground brine water– containing dangerous levels of radiation, heavy metals, and other contaminants — mixed with the fracking chemical-laden fresh water that has been pumped into the well. The chemicals used in the fracking process are known carcinogens, while others remain entirely secret (or “proprietary” by industry), even to the personnel in the field who are employed to use the additives.
Flowback is disposed of by injection into underground wells, in water treatment plants, or in open air pits. Each of these disposal methods comes with enormous risks, such as contamination of drinking water sources, fresh water contamination, inducing seismic activity in the case of underground injection, human exposure to radioactivity, and increased traffic needed to transport produced water.
Produced water, which flows out of the shale throughout the lifetime of the well, contains fewer of these chemicals used to frack the well, itself. Sometimes produced water is treated to remove remaining fracking chemicals and is then reused in the fracking process. However, because fresh water is less expensive to obtain — at least in non-arid parts of the country — this accounts for only a portion of the water used to stimulate a given well.
Shockingly, some states allow for fracking wastewater to be treated and used for agricultural purposes, for road spreading, or for commercial sale in products such as pool salts, increasing exposure pathways to toxic chemicals.
Scroll down to explore articles on FracTracker’s work as it relates to fracking waste issues.
Class II Injection Wells
Class II underground injection wells are a major disposal pathway for liquid oil and gas exploration and production wastes. Much of the solid waste from oil and gas wells will end up in landfills or other types of impoundments, as well as spread on the surface (called land-spreading).
Class II Wastes Include:
- Produced water
- Drilling fluids
- Spent well treatment or stimulation fluids
- Pigging wastes
- Gas plant wastes (including Amine and Cooling tower blowdown)
For disposal, the majority of the liquid is pressed from the solid waste and re-injected back into the ground into Class II injection wells. These liquids are a combination of drilling mud compounds, hydraulic fracturing chemicals, well cleansing acids, and formation fluids. These fluids can be high in naturally occurring radioactive materials (NORMs), hydrocarbons, heavy metals, and other toxics. Such a disposal process is regulated by the U.S. EPA’s underground injection control program, with primacy (authority) granted to states to regulate permitting (COGCC in Colorado, DOGGR in California, RRC in Texas, PADEP in Pennsylvania, Ohio EPA in Ohio, etc.).
This is all outlined in Resource Conservation and Recovery Act (RCRA) Subpart C on Exempt Waste. But because RCRA’s exempt status here is based on the relationship of the waste to exploration and production operations, and not on the chemical nature of the waste, it is possible for an exempt waste and a non-exempt hazardous waste to be chemically very similar.