DENVER (AP) -- Authorities are investigating after construction crews discovered a problem with a liquid gas pipeline that allowed a carcinogen to seep into the ground near a large creek that feeds into the Colorado River.
The leak near an energy plant in Western Colorado was discovered largely by accident, even though several state and federal agencies are charged with monitoring gas pipelines in the state.
"It's possible that we've narrowly dodged a bullet this time," said Michael Saul, with the National Wildlife Federation.
The breach, however, should be a "wake-up call" for involved agencies, he said, underscoring concerns over the risk of a larger danger.
The problem in Parachute, Colo., has allowed thousands of gallons of benzene and other liquid hydrocarbons to seep into the ground.
"It's actually a good thing they found it," said Tom Droege, a spokesman for Williams, the energy company that runs the pipelines and nearby gas processing plant.
If benzene or other hydrocarbons were to get into Parachute Creek, it could taint drinking water and irrigation channels, affecting even the Colorado River.
Authorities say the creek isn't at risk, noting that affected groundwater is flowing away from the creek and that barriers have been set up to minimize any potential contamination.
Officials from the Environmental Protection Agency, the Colorado Oil and Gas Conservation Commission, Williams and WPX Energy, which owns the property, are investigating.
The problem with the line — which investigators characterize officially as a "seep" — so far has generated more than 5,900 gallons of loose liquid hydrocarbons and nearly 180,000 gallons of contaminated groundwater. And many see it as a close call that officials should take as a serious threat.
At least five state and federal agencies play a role in regulating and monitoring pipelines in Colorado, an overlap that causes obvious confusion, illustrated by the accidental discovery of a problem that otherwise could have gone unchecked.
Williams workers, looking to expand a pipeline near the Parachute Creek Gas Plant, were doing routine soil evaluations when they found the presence of unknown hydrocarbons, a find that eventually led to the discovery of the problem with the line. Before that there had been no warning signs.
Unless leaked liquid natural gas or oil "would have come up to the surface, or a pipeline lost pressure, there's no other way to my knowledge to know if there's a leak," said Droege, the company spokesman.
Gas companies can't easily check the integrity of buried pipelines, which can corrode and eventually leak. For its part, Williams constantly monitors pressure levels, since a drop can signal problems, company officials say.
The uncertainty over government oversight provides little reassurance.
The Colorado Oil and Gas Conservation Commission, a division of the state's Department of Natural Resources, oversees the pipelines that run from a nearby well to the processing facility.
The Public Utilities Commission is responsible for pipelines that distribute gas to customers and for on-shore gas gathering lines.
The Federal Energy Regulatory Commission monitors interstate natural gas lines and sets standards for the construction of new lines.
The state's Water Quality Control Division, part of the Department of Public Health and Environment, also monitors the environmental impacts of pipeline construction.
Once pipelines are in the ground, they generally fall under the jurisdiction of the Pipeline and Hazardous Materials Safety Administration, a division of the U.S. Department of Transportation.
And the ruptured pipe in Parachute falls to yet another agency — the Occupational Safety and Health Administration, part of the U.S. Department of Labor, according to Droege.
OSHA has not returned phone calls or an email from The Associated Press seeking comment.
"The regulations can be overwhelming until you get familiar with them," said Jeff Farrells, executive director of the Pipeline Association for Public Awareness, an industry group, on Tuesday.
A report last year by the Government Accountability Office, the nonpartisan congressional watchdog, found that of 40,000 miles of hazardous liquid gathering pipelines, only 4,000 are subject to federal oversight. And of more than 200,000 miles of natural gas gathering pipelines, only 2,000 are federally regulated, the GAO found.
The monitoring system has not kept up with the growth of pipelines, said Carl Weimer, executive director of the Pipeline Safety Trust, a nonprofit industry watchdog. Many lines that were once too small or too remote to pose much of a threat are now high-pressure lines running through high-population areas, he said.
Whether the Parachute seep was the result of failed oversight, lack of regulation or something else entirely, Weimer said it's an important reminder that pipeline problems are a real threat.
"It happens more often than people would believe," he said.