The Alberta Energy Regulator has laid five charges against Nexen Energy for a pipeline spill two years ago that was one of the largest in provincial history.
About five million litres of emulsion – estimated to be roughly a third bitumen and two-thirds water and sand – leaked into muskeg near the company's Long Lake oilsands facility southeast of Fort McMurray.
The charges include releasing a substance that may have caused an adverse effect and disturbance to public lands, failing to report the release as soon as possible, and failing to take all reasonable measures to remediate and manage the spill.
"Producing oil or gas in Alberta comes with a responsibility to follow all requirements to protect the public and environment," said AER president Jim Ellis in a statement.
"When we believe that the rules are not followed, we have a variety of tools, including laying charges that we can and do use in an attempt to ensure that potential offenders are held accountable."
The AER said the company faces a maximum fine of $3-million for the charges.
Nexen spokeswoman Brittney Price said in an email that the company will consider the charges, but will not make any further comment because the matter is before the courts.
The AER's investigation into the pipeline spill – estimated to have contaminated about 22,000 square metres – is still considered active. AER spokesman Jordan Fitzgerald said the findings won't be released until after court proceedings are finished so as to not to taint the process.
Nexen conducted its own investigation into the pipeline rupture, concluding last summer that the design was incompatible with the ground conditions and buckled as the temperature fluctuated.
When it released its findings, Nexen said that along with its own deficiencies, it found a number of failings on the part of contractors and subcontractors during the design, construction and installation of the pipeline.
The company estimates that the pipeline leaked for close to a month before the spill was discovered by a field worker, saying that shortcomings in the pipeline's automation leak-detection system and its ability to manage the system delayed finding the leak.
The Long Lake operation had another major incident in January 2016, when an explosion at the plant killed two workers and knocked the upgrader out of commission. Alberta Occupational Health and Safety continues to investigate.
Nexen, a subsidiary of Chinese state-owned firm CNOOC Ltd., is scheduled to have its first court appearance on the AER charges on Aug. 16, 2017 in Fort McMurray provincial court.