The devastating flooding that pummeled Colorado the past week, also inundated a main center of the state's drilling industry, temporarily bringing production of natural gas to a halt. The mix of floodwaters and drilling operations has also spurred environmental and health concerns that industry and government officials say they are closely monitoring, and that activists have seized on as another demonstration of the dangers posed by hydraulic-fracturing.

Pictures and videos that cropped up on anti-fracking sites and in local news outlets in recent days show inundated oil pads, flooded wells, and, in some cases, overturned tanks and ruptured lines. Many were reportedly captured in Weld County, an area northeast of Denver and Boulder that was hit hard by the flooding. With nearly 18,000 active wells, it's also a main drilling center in Colorado, a state that increasingly relies on hydraulic-fracturing for its energy production.

"Water pollution is the biggest concern," said Gary Wockner, the Colorado program director for the anti-fracking group Clean Water Action. "Our biggest fear is that oil and gas hydrocarbons and hydrofracking chemicals will get into the water supply, and that the flooding will spread the pollution over a large swath of the landscape." While industry representatives have downplayed what one executive called the "social media frenzy" of photos and videos due to lack of information, they have taken steps to mitigate concerns, including stopping the flow of oil at potentially affected wells, a process known as shutting in. Doug Hock, the director of public relations for Encana Oil & Gas which operates a number of wells in the area, said that of the 1,241 wells Encana operates in the energy-heavy Denver-Julesburg Basin, 397 were shut in last week. Since then, 99 of those shut in have returned to production.

"We still have not found any spills of any reportable quantity, but cannot rule out future discoveries until we get to everything," Hock said Tuesday. For their part, Colorado officials have been "aggressively assessing the impacts of the flood to oil and gas facilities," Colorado Department of Natural Resources spokesman Todd Hartman said in a statement. Officials note that there's still limited information concerning the status of the area's oil and gas locations, but are warning about the potential health risks associated with hazardous materials in the flood water. "The Colorado Department of Public Health and Environment is advising Coloradans that many contaminants, such as raw sewage, as well as potential releases of chemicals from homes, businesses and industry, may be contained in the floodwaters," Hartman said in his statement." People are encouraged to stay out of the water as much as possible."