Natural gas drilling could put trees at risk, a new study shows.

RODALE NEWS, EMMAUS, PA—The fossil fuel industry and many politicians are hailing natural gas as America's answer to its domestic energy needs. The problem is, as drilling takes hold across the country—both conventional and hydraulic fracturing, or fracking—independent scientists are finding major threats to human and environmental health. In the latest evidence that natural gas drilling poses serious risks, scientists with USDA Forest Service in West Virginia found that drilling fluid applied to forest land flat-out kills trees and vegetation. "The fluid application was part of the development of a conventional gas well, and was a standard operation," notes Mary Adams, PhD, research soil scientist, USDA Forest Service. "The energy exploration company used fluid in the drilling and fracturing and what came back up was stored in an open pit, until it was land-applied."

Dumping the fluid, a mix of secret chemical formulations and underground contaminants, was legally permitted in the West Virginia forest. "The fluid was pumped from the pit and sprayed onto the forest," explains Adams. Her team of scientists noted the immediate negative consequences—ground vegetation browned and died in just days. Two years later, researchers have found that 56 percent of the trees in the dumping area are now dead. (Dumping of natural gas drilling fluids is allowed in some states.)

Although it's not clear which chemicals ended up being applied to the forest (hundreds are often used in fracking), researchers were able to ID soil concentrations of sodium and chloride increased 50-fold after spraying the compound into the forest…we're talking saltier than ocean saltwater.

This latest research comes as independent scientists show natural gas drilling creates toxic air pollution, drinking water pollution, and worsening climate change emissions.

(For more on the natural gas drilling boom, how some university research projects are sponsored by the natural gas industry, and citizens' stories, listen to This American Life's natural gas segment.)

For more information about natural gas drilling practices and health risks, check out the following Rodale.com stories:

• 5 Facts about Fracking Every Family Needs to Know

•  Water on Fire! Check Out This Fracking Rap

• Natural Gas "Fracking" Threatens National Water Supply, Human Health