It is used to characterize the hydraulic fracturing fluid to help determine the injection profile and location of fractures created by hydraulic fracturing.

Although there may be unconventional fracturing fluids, the more typically used chemical additives can include one or more of the following:

Researchers have recommended requiring disclosure of all hydraulic fracturing fluids, testing animals raised near fracturing sites, and closer monitoring of environmental samples.

The proposed act would require the energy industry to disclose the chemical additives used in the hydraulic fracturing fluid.

A key question is whether the unauthorized injection of hydraulic fracturing fluids containing diesel fuel is adversely affecting drinking water supplies.

We urge you to examine the use of hydraulic fracturing fluids containing diesel fuel as part of your investigation into the industry's practices.

Radioactive tracer isotopes are sometimes injected with hydraulic fracturing fluid to determine the injection profile and location of created fractures.

Because EPA is also examining this issue, we are writing to share our findings regarding the use of diesel fuel in hydraulic fracturing fluids.

EPA has raised concerns about the potential public health risks posed by diesel fuel used in hydraulic fracturing fluids.

Between 2005 and 2009, approximately 10.2 million gallons of hydraulic fracturing fluids containing at least one carcinogen were used.