Suncor working to expel cancer-causing benzene from under Denver-area refinery POSTED: 03/01/2012 01:00:00 AM MST UPDATED: 03/01/2012 08:23:43 AM MST By Bruce Finley The Denver Post
A view from the confluence of Sand Creek and the South Platte River shows the Sand Creek aeration system that Suncor Refinery, pictured in the back, is using to expel benzene from the water. Air bubbles can be seen surfacing halfway upstream in Sand Creek. (Helen H. Richardson, The Denver Post)
Suncor Energy has expanded the hose system blowing air bubbles into Sand Creek attempting to expel cancer-causing benzene spreading from under the company's oil refinery north of Denver.
Its crews also have been packing a trench with bentonite clay from Wyoming, focused on meeting a deadline today for the completion of a 1,000-foot-long, 30-foot-deep underground wall designed to hold back contaminated groundwater.
But benzene levels in Sand Creek and the South Platte River remain significantly elevated — as much as 100 times higher than the U.S. health standard.
Three months after state regulators ordered an intensified cleanup, the fouling of northeastern Colorado's main waterway continues — illustrating the difficulty of dealing with one of the Rocky Mountain region's long-running cases of industrial pollution.
A Denver Post analysis of water sampling data shows that the benzene levels in the creek and river may be increasing.
• At the confluence of Sand Creek and the South Platte, the latest test results show an average benzene concentration of 460 parts per billion in February, up 29 percent from an average of 356 ppb in December. The average for the past eight samples, taken in January and February, was 511 ppb. The federal drinking-water standard is 5 ppb.
• Farther downstream, beneath a bike bridge on the South Platte, tests show an average benzene concentration in February of 241 ppb, up nearly 10 percent from 220 ppb in December.
• Benzene measured in the past two weeks at a series of surface wells along Sand Creek also remained elevated: 170 ppb, 110 ppb, 93 ppb and 89 ppb.
The data, from samples taken by Suncor and provided to the Colorado Department of Public Health and Environment, were provided to The Post in response to written requests.
90,000 barrels a day
Since the 1980s, CDPHE officials have known about and tried to deal with contamination at the refinery north of Denver, where Suncor processes 90,000 barrels a day of crude oil from the region and tar sands piped in from Canada. Suncor purchased the refinery from Conoco in 2004.
In 2008, CDPHE officials signed off on proposed "final measures" for corrective action under Colorado's hazardous waste laws.
Then, on the Sunday after Thanksgiving, a fly-fisherman spotted black goo oozing into the creek and river — and called CDPHE's emergency line. State spill-response coordinators dispatched a county inspector, who found no problem. U.S. Environmental Protection Agency experts responding to a Denver Post query went to the scene and launched an emergency cleanup.
State officials in February 2011 received a report from Suncor about a spill at the refinery likely to worsen problems. But the resurfacing of toxic material in November "was a surprise," said Rob Beierle, the health department environment-protection specialist tasked with overseeing Suncor's cleanup.
The continuing seepage of benzene into the creek and river "is a concern," Beierle said in an interview over diagrams and maps. "We need to clean it up.
"I think we've got a pretty good idea of what's going on. We just need to run Suncor along as fast as we can. It takes time to clean up subsurface contamination."
"Not the final solution"
This week, Suncor vice president of refining John Gallagher said aerating Sand Creek to release trapped benzene is not producing the results the company had hoped to see. This "is not the final solution," he said.
Company officials and state regulators now envision a combination of cleanup methods, including pumping and treating 500 gallons of contaminated groundwater per minute and removing toxic vapors from soil.
"We are applying significant resources to address the problem of underground contamination and will continue to do so until we make it right for the environment and this community," Gallagher said.
Gallagher also noted that, under CDPHE's current system for classifying the state's waterways and setting thresholds for pollution, the amount of benzene allowed into Sand Creek is 5,300 ppb — far above the federal 5 ppb health standard.
"Based on the fact that the benzene standard is 5,300 ppb, we don't anticipate there is any permanent damage to the Sand Creek environment," he said.
The harm from spilled benzene probably depends on when contaminated groundwater first reached waterways and how fast it can be contained and cleaned. State aquatic biologists have raised no concerns.
"Cancer in aquatic life, like fish, or in humans who use the water as drinking water might take a decade or two to show up," said Joe Ryan, an environmental engineer at the University of Colorado. "Fish would be much more susceptible to the hazard than humans."
Suncor's underground wall "should have an immediate benefit by slowing the groundwater flow," Ryan said.
But eventually groundwater may find a way around the walls, and "something will have to be done to remove the source of the benzene and the benzene in the groundwater trapped by the wall," he said.
No contamination of drinking water is expected because municipal water providers who rely on the South Platte below the confluence with Sand Creek — Aurora and Thornton — treat their water to remove contaminants before water is piped to homes.
Agricultural irrigators also are tracking the situation, as are water-diversion pipeline operators. The Burlington Ditch, lined with concrete in the 1980s, is not connected with Sand Creek, and water sampling at Barr Lake near Brighton has not detected new pollution.
Beyond the refinery, groundwater contaminated with benzene has spread under neighboring property, including Denver Metro Wastewater's Robert Hite Treatment Facility. Metro Wastewater managers there have given Suncor access to build the underground wall and "are concerned for our workers' and contractors' health and safety, and to meet all of our obligations under our (state pollution) discharge permit," agency spokesman Steve Frank said.
Meanwhile, Herb Gibson, Denver-area director for the U.S. Department of Labor's Occupational Safety and Health Administration, anticipates his open investigation of worker exposures to benzene will continue for several months.
The investigation has expanded beyond refinery locations where benzene was found in drinking water to include benzene in air, Gibson said. "We have received complaints."
Benzene apparently penetrated plastic pipes. Suncor still is providing bottled water for drinking. All Suncor workers have had their blood tested.
The overall situation forced a CDPHE reassessment of corrective actions approved several years ago. By the end of this month, Suncor now is obligated to build an additional 2,000-foot-long underground wall at the edge of the refinery property.
Ways to extract benzene
Cleanup plans also call for continued use of systems designed to extract benzene vapors from soil. About 300 wells drilled around Suncor's property are used to try to monitor the movement of benzene and other toxic contaminants in groundwater. Two pre-existing underground barriers are meant to slow the spread of contaminated groundwater.
Heavy machinery reverberated this week as contractors filled trenches along Sand Creek with the bentonite, which expands upon contact with water to form what is meant to be an impenetrable barrier.
Suncor supervisors said that once this wall is completed, they'll move machinery to start work on the new, bigger underground wall.
"When Suncor purchased these properties from other owners, the ground under the refinery was already contaminated," Gallagher said.
"Suncor is not perfect. We've had some spills on our site that have added to the contamination. It is our intention — and part of the plan that we're following with CDPHE — to remove and recover all of the hydrocarbons in the soil that is practical.
"The uses of our property and neighboring industrial properties will remain the same as they have been prior to this incident."
Bruce Finley: 303-954-1700, twitter.com/finleybruce or firstname.lastname@example.org