The oil and gas industry’s claim that there is no evidence linking hydraulic fracturing to negative impacts on human health is crumbling bit by bit as new scientific evidence comes in.

Today we have new evidence that fracking waste water contains high levels of hormone-disrupting chemicals. According to Susan Nagel of the University of Missouri School of Medicine, these chemicals “could raise the risk of reproductive, metabolic, neurological and other diseases, especially in children who are exposed to EDCs [endocrine-disrupting chemicals].” Nagel is one of the authors of the study, which has been accepted for publication in The Endocrine Society’s journal Endocrinology.

The report’s description of the study’s methodology:

Researchers took surface and ground water samples from sites with drilling spills or accidents in Garfield County, Colo. The area has more than 10,000 natural gas wells. Researchers also looked at control samples from sites without spills in Garfield County, as well samples from Boone County, Missouri.

The water samples from drilling sites had higher levels of EDC activity that could interfere with the body’s response to the reproductive hormone estrogen, and androgens, a class of hormones that includes testosterone.

Drilling site water samples had moderate to high levels of the hormone-disrupting chemical. Water samples from the Colorado River, which is the drainage basin for the natural gas drilling sites, had moderate levels.

Researchers found little EDC activity in the water samples from the sites with little drilling.

If you’re thinking, “They only found problems in samples taken from wells with spills. ECA touts their great safety record, so we won’t have that problem here,” think again. In the Bakken in North Dakota, there have been over 750 oil field “accidents” and 300 spills since January 2012. Montana, like North Dakota, doesn’t regulate drilling. There will be spills on the Bearfront too.

In an ecosystem as fragile as ours, the introduction of EDCs into the water system will be devastating. Note that the EDCs are found not only in the groundwater, but have made their way into the Colorado River.