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The Endocrine Disruption Exchange
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Oil & Gas Program

Many chemicals associated with oil and gas operations are endocrine disruptors. This includes chemicals used to facilitate oil and gas extraction, and those released from deep within the earth during the process. Chemicals retrieved from underground rock formations are valuable feedstock chemicals that are refined and synthesized into thousands of other chemicals used in industrial and consumer products, many of which are also endocrine disruptors.

TEDX was one of the first organizations to recognize the potential health impacts of exposure to chemicals associated with hydraulic fracturing, a relatively new process of extracting oil and gas that has spread rapidly across the US and the world. Since then we have been creating tools to share the latest science on the health effects associated with unconventional oil and gas production. This includes a database of published research, spreadsheets of the potential health effects of drilling, fracking, and wastewater chemicals, recorded videos, webinars, and calls with leading scientists, and our own published peer-reviewed scientific papers. See our menu of resources to the left. 

How are unconventional wells drilled?

Wells are drilled down thousands of vertical feet into oil and gas bearing formations. Drilling “muds” containing weighting agents, emulsifiers, and lubricants are used to help move the drill bit down the well bore. Surface casing using steel pipes and cement is then inserted to help prevent the movement of fluids and gases into groundwater. After the vertical hole is drilled, the drill bore can be extended horizontally for over a mile in multiple directions.

HOw does hydraulic fracturing work?

Hydraulic fracturing (fracking) is the process of injecting liquid at high pressure to open up tight rock formations to release oil and gas. After a borehole is drilled, small explosions are set off along the wellbore to punch holes in the well casing. Millions of gallons of water mixed with proppants (usually silica sand) and chemicals are injected under high pressure using diesel-powered heavy equipment. Pressure forces the rock to fracture and then the proppant holds the fractures open so that the gas or oil can be collected. Chemical products used for fracking include biocides, solvents, corrosion and scale inhibitors, friction reducers, and surfactants.

What is wastewater (produced water and flowback)?

Two types of wastewater from oil and gas operations are “flowback” and “produced water”. Flowback is fluid that resurfaces in the first few weeks after fracking, typically 30%-70% of the total injected fluids. Produced water is a mixture of water and chemicals that surfaces from underground, sometimes for the life of the well. Heater-treaters on the pad are used to separate the water from the gas and heavier liquid hydrocarbons including oil and condensates. Flowback and produced water can be stored in pits or tanks on the pad, or trucked or piped off-site. They are then injected into deep injection wells, pumped into large evaporation ponds, recycled for reuse in fracking operations or for ‘beneficial’ reuse such as irrigation or livestock watering. 

How can the air be polluted?

Air pollution has two primary sources: volatile chemicals pumped into the ground during drilling and hydraulic fracturing, and raw gas released from underground, which contains toxic air pollutants. Wells may be directly vented or flared (burned) for several days, weeks or even months, until connected to a pipeline. Pollutants also escape from equipment and storage tanks on well pads, and from off-site transmission pipelines and compressor stations. Diesel exhaust from running large equipment on the pad and the hundreds of truck trips needed to develop and maintain a well site also contribute volatile organic compounds as well as fine particulate matter to the air.

How can water be contaminated?

Groundwater can be contaminated by gas migrating from faulty well casing and cementing. Contamination of shallow aquifers and surface water has been linked to spills and leaks of fracking fluids and wastewater on the well pad. Further, improper treatment and disposal of wastewater can contaminate streams and rivers.