St. Paul Park refinery fined in benzene wastewater case
Regulators penalized St. Paul Park Refining Co. for improperly handling wastewater containing benzene, a hazardous liquid that could have been released from the oil refinery into the nearby Mississippi River.
The Minnesota Pollution Control Agency fined the company $40,000 for that and other violations, mostly related to the improper toxic chemical storage at the St. Paul Park facility. The civil penalty was part of a stipulation agreement between the MPCA and the company, a division of Northern Tier Energy.
The company signed the agreement but did not agree with the allegations, said Paul Anderson, who handles Northern Tier’s government and community relations. There were four corrective actions required in the agreement, and the company has completed all of them, Anderson said.
The improper wastewater handling occurred from Jan. 4, 2011, to Sept. 10, 2012. The company discharged more than 4 million gallons of the wastewater into an unlined lagoon at the refinery. The liquid contained 2.7 gallons of benzene, the MPCA said.
An MPCA announcement of the penalty last week said liquid from the unlined lagoon could migrate to shallow groundwater before reaching the river. However, Anderson said there was no proof that wastewater containing benzene left the lagoon.
Environmental rules cover both actual and potential toxic releases, said Sam Brungardt, an MPCA spokesman.
Crude oil is refined into gasoline and other fuel products at the refinery. Crude oil contains benzene, as do refined products. Normal wastewater treatment involves removing benzene from water and reusing it in the refining process.
Northern Tier Energy purchased the refinery in December 2010. At that time, the refinery’s wastewater treatment plant was not properly removing benzene from the wastewater. Storing wastewater in the lagoon was part of the treatment process.
In 2012, the MPCA leveled a $700,000 civil penalty against the refinery’s previous owner, Marathon Petroleum, for its similar failure to properly treat the wastewater containing benzene. The penalty was much higher in that case because Marathon Petroleum’s violation involved some 114 million gallons of wastewater.
As part of its corrective actions, St. Paul Park Refining installed a new, $42 million wastewater treatment plant that contains the water being processed and does not use a lagoon. The new plant, which went online in June, is located on the site of the former lagoon, Anderson said.
“It’s the condition of the lagoon they were concerned about,” he said. “From our perspective, our agreement was to go ahead and get that lagoon closed.”
The company had other violations related to the wastewater storage infraction. The MPCA said St. Paul Park Refining operated without a hazardous waste facility permit; improperly managed the facility to minimize unplanned hazardous waste releases; and failed to send 117 signed manifests to the state agency and was late with two others.
A separate violation involved the improper storage of a 55-gallon drum of hazardous waste mercury. Anderson said the drum was on site longer than is allowed, due to a date error on the drum. The company collects mercury from old thermometers and other equipment on site and must follow certain disposal requirements.
The MPCA also said the company failed to report and clean up a spill of untreated wastewater containing hazardous waste.
“We continue to work with the MPCA to ensure environmental responsibility of our operations,” Anderson said.