Colorado state authorities agreed over the weekend that going forward the mitigation of a natural gas liquids (NGL) spill near Parachute Creek will be led by the state Department of Public Health and Environment (DPHE). The Oil and Gas Conservation Commission (OGCC) will no longer be the lead agency.

The change comes after the recent detection of trace amounts of benzene in an area of Parachute Creek, but OGCC said the shift in oversight “doesn’t reflect any material change in the circumstances at the site, the nature of the spilled hydrocarbons, or any change in what’s currently understood about impacts to groundwater or surface water.”

Both OGCC and the DPHE have been involved with the response to the spill from the outset last month. Under state law, OGCC is responsible for exploration and production (E&P) waste to water spills, but more recently it was concluded that the hydrocarbons released from a Williams Co. NGL line near its processing plant does not constitute “E&P waste.”

Thus, the change is a result of a legal interpretation that has classified the spilled materials as ones over which DPHE has primary authority, OGCC said.

In its latest report, Williams said last Wednesday that it has deployed additional resources in focusing on protecting Parachute Creek, where efforts have been focused on a valve box for an NGL pipeline carrying liquids away from a nearby gas processing plant (see Daily GPI, April 1). Part of that response includes installing aeration technology in response to the benzene readings.

“A Parachute Creek sample just upstream of the Colorado River confluence shows no benzene,” Williams said.

Williams characterized the trace benzene amounts detected as being in a “defined” area of Parachute Creek, where ground water is entering the creek. “The area is about 1,500 feet linearly downstream of the pressure gauge that was the source of the NGLs,” the company said.

Since the benzene was detected April 18, Williams has received samples showing maximum benzene readings of 3.9 parts-per-billion (ppb). The U.S. Environmental Protection Agency standard for safe drinking is 5 ppb, Williams said.

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