Eleven chemicals commonly used in the fracking process are endocrine disruptors, and surface and ground water near drilling sites has greater hormone-disrupting properties than water near areas without drilling, according to a new report by researchers with the University of Missouri.

“The rapid rise in natural gas extraction utilizing hydraulic fracturing increases the potential for contamination of surface and ground water from chemicals used throughout the process,” researchers report. “Hundreds of products containing more than 750 chemicals and components are potentially used throughout the extraction process, including over one hundred known or suspected endocrine disrupting chemicals.”

Researchers tested 12 suspected or known endocrine-disrupting, or hormone-altering, chemicals used in the hydraulic fracturing process and measured their ability to both mimic and block reproductive sex hormones. They found that 11 of the suspected or known endocrine-disrupting chemicals blocked estrogen hormones, and 10 blocked androgen hormones, the University of Missouri (MU) School of Medicine reports. One chemical mimicked estrogen.

Researchers collected surface and ground water samples from multiple sites, including sites in Garfield County, Colorado where fracking fluids have been spilled, portions of the Colorado River, parts of Garfield Country where little drilling occurred, and parts of Boone County, Missouri where no drilling had occurred.

Water samples taken near drilling sites had moderate to high levels of endocrine-disrupting activity while samples from sites that experienced little or no drilling had low levels of endocrine-disrupting activity.

“Fracking is exempt from federal regulations to protect water quality, but spills associated with natural gas drilling can contaminate surface, ground and drinking water,” said Susan Nagel, PhD associate professor of obstetrics, gynecology, and women’s health at the MU School of Medicine.

“We found more endocrine-disrupting activity in the water close to drilling locations that had experienced spills than at control sites,” she added. “This could raise the risk of reproductive, metabolic, neurological and other diseases, especially in children who are exposed to endocrine-disrupting chemicals.”

Endocrine-disrupting chemicals can interfere with the body’s endocrine system, producing “adverse developmental, reproductive, neurological, and immune effects in both humans and wildlife,” according to the National Institute of Environmental Health Sciences. These chemicals can be found in a wide range of everyday products such as plastics, metal food containers, pharmaceuticals, and cosmetics.

Watchdog groups have been working to put pressure on lawmakers and spread public awareness about the dangers of hormone-altering chemicals; however, the regulatory process will have to be altered and safer substitutes found in order to replace harmful chemicals.

Now humans and animals may be exposed to hormone-altering chemicals through water as a result of fracking. “With fracking on the rise, populations may face greater health risks from increased endocrine-disrupting chemical exposure,” Nagel said.

In other research, endocrine-disrupting chemicals have been linked to certain cancers, developmental risks in fetuses and children, and infertility.

Alisha is a writer and researcher with Ring of Fire. Follow her on Twitter @childoftheearth.