DENVER - Some monitoring wells near Parachute Creek continue to show elevated benzene levels.
Officials have been conducting tests on groundwater from wells drilled near the creek, which is near an oil-like leak from a Williams Midstream natural gas plant. The Colorado Oil and Gas Conservation Commission updated the results Tuesday.
The results from two of the wells adjacent to the south side of the creek showed benzene levels at 3,300 and 2,600 parts per billion. Another well, about 200 feet east of the creek, showed benzene at 1,200 parts per billion.
These levels are far above the state health standard for benzene, which is 5 parts per billion, according to Colorado Department of Natural Resources spokesman Todd Hartman.
Testing two weeks ago showed benzene at a range of 5,800 parts per billion to 18,000 ppb, Hartman said.
Meanwhile, three other wells about 50 feet away from the south side of the creek came back with no detection of benzene.
For the first time since March 9, the sampling found the presence of Diesel Range Organics in surface water. The first detection was at a location 800 feet upstream of the activity area, on the other side of a road bridge, and at two other locations near the activity area.
Three surface water sampling points downstream did not detect Diesel Range Organics.
Diesel Range Organics include diesel fuel and its by-products.
The COGCC says it continues to share details of the site with the leadership of the U.S. Environmental Protection Agency and the Colorado Department of Public Health and Environment.
The town of Parachute and Williams have agreed on a process for Williams to begin water sampling at the point downstream where the town diverts water to an irrigation reservoir.