The former Marathon Oil refinery in St. Paul Park has paid a $700,000 penalty for releasing benzene into an unlined lagoon adjacent to the Mississippi River.
The Minnesota Pollution Control Agency said Marathon gained financially by illegally disposing of more than a million gallons of benzene process wastewater in 2010. Benzene is a potent carcinogen.
The MPCA also says Marathon lacked a permit for hazardous waste, and exceeded its permit limits for ammonia, nitrogen and sulfides.
Late in 2010, Marathon sold the refinery to St. Paul Park Refining Company, which currently operates the facility.