Technically I suppose that should be Day 370-something because it has been more than a year since the leak originally occurred. However my count began on the March 8, 2013, the date on the original spill report (Form #19).
Benzene near site drops [subscribers only]
Williams is reporting sharp reductions in groundwater benzene levels at a natural gas liquids leak site near Parachute Creek, although areas with high concentrations remain.
Williams has submitted a contingency plan for the inevitability of when flooding occurs and benzene once again reaches the creek as it did last summer.
Williams continues to work on the cleanup of the leak, which it believes happened about a year ago, from Dec. 20, 2012, to Jan. 3 of last year.
The leak was blamed on a faulty valve pressure gauge on a pipeline connected to Williams gas processing plant. The company did not report the leak to the COGCC on January 3, 2013 when they discovered the problem with the pressure gauge. In March, a massive underground plume was uncovered during an excavation which was allegedly for a plant expansion project that never happened. The plume was eventually determined to be approximately 1,500 feet long, 308 feet wide and 10 feet thick.
Williams eventually estimated that about 10,000 gallons of hydrocarbons entered soil and groundwater. It believes it has recovered about 8,555 gallons to date.
According to a December 16 update at Williams website, Answers for Parachute: “Phase I and IIA AS/SVE treatment systems have been very successful in reducing dissolved-phase benzene concentrations in groundwater. Key monitoring points have seen reductions of 90-100%.”
According to a recent update Williams provided to the Colorado Department of Public Health and Environment, some monitoring wells that once had benzene at levels of up to 2,400 parts per billion now are reading at less than 1 ppb. The safe drinking water standard for benzene is 5 ppb.
But readings at some sites remain much higher, including one site with a reading of 68,000 parts per billion. Williams spokesman Tom Droege said Friday that monitoring point “is located directly within the central area where the release occurred and liquid hydrocarbons are present, which significantly impacts the groundwater sample there.”
Williams is working to eliminate those hydrocarbons through means including pumping up groundwater, cleaning it and returning it to the aquifer …
… [The potential for flooding] has been a concern for Bob Arrington, who lives in nearby Battlement Mesa and believes that a flood in the creek on Aug. 23 may have shown the need for such a plan. That flood damaged booms in the creek and other equipment, although no sheens or other indications of contamination on the booms or in the creek were seen in daily inspections afterward.
“I think it was an eye-opener for them,” said Arrington, who said it’s possible diluted amounts of benzene still reached the creek.
None was detected in the creek in Aug. 26 testing.
Howard Orona, whose home draws water from a shallow well near the creek, said the flood left him more concerned that other oil and gas infrastructure up the Parachute Creek Valley might be damaged and leak. But he also was impressed by Williams’ response, and said it had people on the scene pretty quickly.
For more information and access to documents visit CDPHE Parachute Creek
Under Documents the most recent report is the Monthly Progress Report November 2013 – which is dated December 13, 2013.