As Colorado reels from a prolonged flooding disaster that has killed at least eight people and left hundreds unaccounted for, environmental groups warn of potential contamination by ruptured oil and gas industry infrastructure.
In Weld County, which has seen some of the worst of the rains, activists point to photos of destroyed wells, tanks and pipelines posted on social media sites. They claim that years of “fracking,” the process of drilling for shale gas through hydraulic fracturing, has made the area northwest of Denver and Boulder vulnerable to contamination in the event of flooding.
"Weld County, where the South Platte River has been flooding uncontrollably, has almost 20,000 active oil and gas wells," Gary Wockner, Colorado program director for Clean Water Action, told Al Jazeera.
"It's the most heavily drilled county in the U.S., and it's seeing some of the worst flooding," he said. "Oil and gas and chemicals associated with drilling are going to be spread across a wide swath of landscape."
The latest flood began last Wednesday, triggered by unusually heavy late-summer storms that drenched the northeastern part of Colorado. Along with Weld, the counties of Boulder, Adams, Jefferson and Larimer have been the worst hit.
There are hundreds of active oil and gas wells built in the South Platte River floodplains alone that are at risk of contaminating the floodwaters. Already there have been reports of a ruptured natural gas pipeline and overflowing crude-oil wells. By Wednesday evening, the Denver Post was reporting that crews had placed absorbent beams into the South Platte River south of the town of Milliken, where it said 5,250 gallons of oil had spilled into the river.
Ahead of that news, industry representatives had attempted to downplay any risk, suggesting that the pictures of broken pipes and underwater wells amount to a “social media frenzy.”
Tisha Schuller, president of the Colorado Oil and Gas Association, testified before the Colorado Oil and Gas Conservation Commission regarding the industry's response to the historic floods, which have forced the evacuation of more than 10,000 people.
"All impacted wells have been shut in, which means the well has been closed off or shut and is not producing any oil and gas product," Schuller said in a release.
Schuller also responded to controversial photos that Colorado residents have uploaded to social media sites showing floating tanks, blowouts and flooded infrastructure.
"We have seen the social media frenzy regarding pictures of oil and gas facilities 'under water,'" she added. "While the pictures seem extraordinary, there is no data or specifics provided."
The photos and videos have not been independently verified by Al Jazeera.
Wockner, meanwhile, said he had seen "a number of photos online that show wells underwater and big tanks either floating or toppled," and that the risk of contamination is real.
"These containers have pipes attached to them and can hold 5,000 gallons or more," he said. "If the tank is floating and tilted, then the pipes are probably breaking off."
Possible contaminants from fracking include toxic chemicals, including cancer-causing benzene, activists point out.
Meanwhile, oil and gas companies have been keen to stress the measures they have brought in to make their pipes and wells safe.
Colorado Interstate Gas Co. declared force majeure -- an event that is the result of elements of nature -- on two of its pipelines in an online statement Monday.
Pipelines became unusable after exposure to "erosion and scouring caused by heavy flooding in the area," according to the statement.
Most industry companies with infrastructure in the affected areas have made statements saying they had "shut in" wells and pipelines before the worst of the flooding began, but they admit it will not be possible to assess the damage fully until the waters have receded.
Anadarko, an oil and natural-gas exploration and production company, said in a press release Tuesday that it had shut in about 670 of its 5,800 wells and about 20 miles of its more than 3,200-mile pipeline.
PDC Energy, meanwhile, said in an online statement that it had suspended production from a "limited number of wells … beginning last Friday due to wide-spread flooding and extensive road closures in Weld County."
Denver-based Xcel Energy said that approximately 50 to 60 feet of a natural gas pipeline was exposed in Boulder County and that crews were at the site to stabilize and support the line.
Gabriel Romero of Xcel media relations told Al Jazeera that thousands of customers were without power after the company shut in wells and pipelines ahead of the worst of the flooding in affected areas.
Romero said that the process of reintroducing natural gas to the lines will be a long one.
"Every inch of the lines must be checked for leaks," he said. "There isn't just a central switch we can turn on … Crews must be sent out to each home to make sure it's safe to reintroduce gas."
But critics say all oil and gas wells in the floodplains should have been shut down before disaster struck, or that they never should have been constructed on floodplains in the first place.
Prior to the flooding, 158 of the state's 309 spills were in Weld County alone in 2013, according to Colorado Oil and Gas Conservation Commission records.
"There are very weak regulations in Colorado around drilling and fracking and having oil and gas operations in floodplains and around rivers," Wockner said. "Every year in Colorado there are a few hundred spills, when oil and gas and fracking chemicals are spilled onto the ground and into waterways."
Mark Salley, spokesman for the Colorado Department of Public Health and Environment, was unable to provide new information about the reported leaks or the risk of contamination from the hundreds of wells in the floodplains.
"I haven't heard that information, and I'm not going to speculate on those risks," Salley told Al Jazeera. "What I can tell you is that we have sent out advisories … about sewage treatment systems that have broken."