The City of Beauharnois is worried a rusting cargo ship in Lake St. Louis is at imminent risk of leaking millions of litres of contaminated water that could end up in the St. Lawrence River.

The Kathryn Spirit was abandoned near the town on Montreal's South Shore, directly south of Île-Perrot, more than four years ago. The derelict ship contains water contaminated by crude oil in its ballast.

Beauharnois recently learned the Mexican company that owned the 150-metre-long ship has renounced ownership after going bankrupt.

As a result, all pumping operations to keep the boat upright have stopped.

Beauharnois Mayor Claude Haineault says rain and snow are accumulating in the hold of the ship, and with the pumping operations stopped, he's worried the ship might begin to list and eventually capsize.

kathryn spirit beauharnois

The Kathryn Spirit, a rusty cargo ship in Lake St. Louis, has been abandoned near the town of Beauharnois for more than four years. (Julie Marceau)

"I think it will be a very big environmental disaster very soon," Haineault said.

A crisis for Montreal

Haineault said Montreal would be most at risk if the contaminated water ended up in the St. Lawrence River.

The Kathryn Spirit is anchored in an environmental protection zone in Lake Saint Louis, the reservoir that supplies drinking water to Montreal.

Haineault said it's just a matter of weeks before the situation becomes critical.

4 years of frustration

The Beauharnois mayor said he's been asking provincial and federal governments to remove the cargo ship for years.

That call for help that was supported by LaSalle last summer when the borough unanimously voted to pass a resolution backing up the City of Beauharnois.

'I wish that somebody somewhere thought this  was an important issue,' - Beauharnois Mayor Claude Haineault

The notes from that council meeting reveal that the city had been warning provincial and federal governments of the ship's "environmental risks to aquatic fauna" since 2011.

The notes also show that Transport Canada maritime officials, while investigating a spill in Lake St. Louis in 2013, mentioned the degree to which the cargo ship was tilted was "precarious and very worrying."

Beauharnois has now asked both governments to step in and help safely dispose of the Kathryn Spirit.

"After four years, we are very frustrated," Haineault said, "I wish that somebody somewhere thought this was an important issue."

Transport Canada says the Kathryn Spirit is now under the jurisdiction of the Canadian Coast Guard.

Calls to the Coast Guard have not been returned.