Canadian National Railway has been fined $2.5 million for an April 2015 spill of diesel fuel into the North Saskatchewan River.

The fine was levied against the railway Thursday in an Edmonton courtroom.

CN pleaded guilty to one violation under the federal Fisheries Act and three charges under the Canadian Environment Protection Act. The Fisheries Act charge related to the impact on fish and wildlife from the diesel spill. The three charges under the CEPA pertained to  the lack of an emergency response plan on site to deal with the incident, using an outdated pipe, and operating a centrifugal-type pump that had been banned from use.

In speaking to sentence, federal prosecutor Erin Eacott said CN was "grossly negligent" by not taking "simple and inexpensive steps" that could have prevented the incident, which occurred when a malfunctioning separator discharged a mix of diesel and water into a storm sewer in CN's Bissell rail yard in north Edmonton on April 9, 2015.

The conviction is one of the first under the amended federal Fisheries Act.

Crown prosecutor Erin Eacott (left), and Daniel Smith from Environment Canada

Crown prosecutor Erin Eacott (left), and Daniel Smith from Environment Canada say $2.5 million for 90 litres of diesel fuel sends a strong message (CBC)

"When you're looking at a $2-million to $2.5-million fine, this sends a strong message of deterrence," said Eacott, who added the fine also helps to make sure industry complies with the law.

 "It's also an important deterrence for CN itself," said Eacott.

During the sentencing hearing, Eacott noted that CN had three previous convictions under the Fisheries Act.

CN was fined  $1.4 million by the province of Alberta and the federal government for a 2005 train derailment that spilled bunker oil into Lake Wabamun, west of Edmonton.

The company was fined $400,000 for a 2005 derailment that spilled caustic soda into the Cheakamus River in B.C., and $75,000 for an oil spill that leaked into the Fraser River in 2009.

The 2015 spill into the North Saskatchewan River was estimated to be 90 litres, court heard Thursday. There was no evidence fish died as a result of the incident. Environment Canada regional director Daniel Smith said the large fine will help contribute to a "healthier and safer river."

"So, $2 million for 90 litres of diesel fuel is a very significant fine, and what we think this does is set a deterrence for anyone operating near water, or near a storm drain."

Spill traced back 8 kilometres 

Smith said CN failed to report the spill to the Alberta Spills Line, forcing Environment Canada officers and the city to trace the diesel fuel eight kilometres back from the river to the source at the CN Bissell yards in north Edmonton. 

"Had it not been for the excellent work of our officers and the City of Edmonton, we would have not known about this, and potentially not been able to hold CN rail to account for their actions," Smith said.

Nicholas Hughes, the lawyer representing CN, said the company accepts full responsibility for the spill.

Earlier this week, Alberta Environment and Parks said CN had been fined $125,000 after the company pleaded guilty to two provincial environmental charges stemming from the same 2015 discharge of diesel fuel into the river.

In an agreed statement of facts, CN acknowledged that when the discharge occurred an alarm system wasn't working. Filters had not been replaced and employees didn't know whose responsibility it was to deal with some of the equipment.