Properties with fracking sites are too risky to insure, according to some experts.

Drilling for natural gas using the unconventional hydraulic fracturing, or fracking, technique has been blamed for manmade earthquakes, toxic water contamination, and destroyed air quality. But it's not just homeowners and environmental activists who recognize the threats, anymore. Nationwide Insurance, one of the country's major property insurance corporations, says the risks associated with fracking "are too great to ignore." Information from an internal memo posted online and a subsequent interview with the Associated Press describes how Nationwide's insurance plans for homes and businesses "were not designed to cover" the unique risks associated with fracking.

The details come as heavy drilling in Pennsylvania, Ohio, Texas, Wyoming, and other areas continues to generate complaints regarding environmental harm, damage to infrastructure, degraded quality of life, and health problems that arise around drilling areas. "Nationwide isn't willing to risk its bottom line over fracking, and our elected leaders shouldn't be willing to risk the health and safety of those they serve," Wenonah Hauter, executive director of Food and Water Watch, said in a statement. "What countless families, farmers, and small business owners across the nation have already figured out—that fracking just can’t be done safely—national corporations with a stake in our land are now realizing, as well."

Fracking involves taking fresh water, mixing it with chemicals linked to autism, hormone disruption, respiratory disease, and cancer, and injecting it deep into the earth to crack open the shale rock formations that contain the gas. (Check out this fracking video for a quick rundown of how it's done.)

Although industry says it recycles the liquid mixture used in fracking, the truth is only up to 15 percent is reused. The rest either stays deep in the shale formations, where's it's lost from the water supply forever, or can potentially migrate into aquifers and contaminate well water.

Earlier this year, a leading group of doctors called for a ban on fracking unless the process could be proven safe. Currently, fracking is banned in New York state, although the state is considering giving industry the go-ahead.