Suncor Energy must do more to contain an underground plume of toxic petrochemicals spreading from its oil refinery in Commerce City, CO, because it is complicating a $211 million upgrade at the adjacent Metro Wastewater Treatment Plant.
A recent groundwater test detected cancer-causing benzene in that area, raising concerns the plume is moving in new directions and prolonging one of the Rocky Mountain region’s longest-running industrial cleanups. On top of that, this plume could potentially delay the wastewater upgrade.
A letter from the Colorado Department of Public Health and Environment (CDPHE) to Suncor’s senior remediation adviser also told Suncor to install more monitoring wells around what inspectors believe is the edge of the plume so they can track it more carefully.
“We want Suncor to have plans in place so that, if something comes up, they can deal with it immediately,” CDPHE hazardous waste corrective unit leader Walter Avramenko said.
The goal of the Metro Wastewater project is to remove ammonia and nitrates from Denver’s treated wastewater before it discharges back into the South Platte River — part of $1.2 billion in improvements at the plant. CDPHE’s water-quality division required the improvements to meet standards set by the federal government by 2015. Metro Wastewater must construct a large aeration basin structure where secondary treatment can occur.
Metro excavation crews have dug out more than 130,000 cubic yards of dirt, pumping groundwater from the emerging hole. Construction crews have begun to build up the new structure.
The toxic plume appears to have approached the excavated area but has not entered it, Metro Wastewater spokesman Steve Frank said.
“What we want from Suncor is to continue working on solving this problem,” Frank said. “We intend to do everything we can to remain in compliance with our discharge permit. Compliance is the norm for us.”
Suncor officials said they will comply.
“We’re meeting with Metro and are working with Metro to understand their construction plans and make sure we do everything we can to allow them to effectively do their work and meet their timelines,” Suncor vice president John Gallagher said. “This is really a potential problem rather than a problem.”
Suncor has been building underground walls and sump systems to remove toxic liquids and vapors spreading from its oil refinery, located northeast of the wastewater plant.
On Nov. 28, officials discovered toxic waste from the refinery spreading directly into Sand Creek and the South Platte. The latest data released by CDPHE regulators shows benzene levels at 400 parts per billion or higher in the South Platte and at two monitoring wells along Sand Creek. The federal drinking-water standard for benzene is 5 ppb. CDPHE officials set a warm-water aquatic life standard that allows benzene at levels up to 5,300 ppb.