REGINA -- The province’s Water Security Agency (WSA) says the risk to the environment and public of oil sludge from the Regina’s Co-op Refinery discharging into the City of Regina’s sewer system on May 22 remains low.

“When this happened, the City of Regina and the operators at the wastewater treatment plant did some good work and they very quickly diverted this issue to another lagoon cell to try and mitigate things,” said Patrick Boyle, a spokesperson for the Water Security Agency.

According to John Hilts, the operations superintendent of the refinery, high winds resulted in stirring up sediments of a lagoon on site resulting in a discharge of sludge into the sewage system.

“It wasn’t an oil spill in the typical sense. All of (the refinery’s) waste water effluent after being treated on site is pumped to the City of Regina’s wastewater treatment plant,” he said. “(The refinery’s) wastewater is going to the city 24/7, 365 days, several million litres per day, we have an effluent agreement to do so. All of that flow goes through our lagoons on site, as a last step before it goes to the city. These lagoons do contain some oil and sediment and that does build up on the banks and the bottom of the ponds. There was an amount of oil in that waste water of where that water flow originated.”

The public was not notified of the spill because Co-op says the “issue was contained.” The WSA says normally when an incident like this happens, the public directly impacted downstream is notified personally rather than hearing it through the media.

“We had asked the city to do some notifications to those downstream so they go that those members of the public got the message and give them that sort of information in what was happening,” Boyle said.

Unifor Local 594 has been in a labour dispute with the Co-op Refinery for six months. Kevin Bittman, President of Local 594 is asking questions about Co-op’s handling of the spill.

“I’ve worked for the refinery for 23 years. I’ve never heard that the winds has caused such a spill like this. This is just a testament at what our people do and the qualified people that run that system are out on the line and if our people were out there, it would have been caught faster and it wouldn’t have had such of an impact on the waste water system,” he said.

“We have a great working relationship with the city, we’re in contact with them regularly and it’s important for us and the city that our interconnected systems are working well and we’re protecting the environment and the public,” added Hilts. 

Co-op said it is conducting its own investigation and that the complex is taking measures to make sure something like this does not happen again. The amount of oil discharged is still not known.

The City of Regina is expected to address the oil spill on Tuesday morning.

The Ministry of Environment did not return CTV News’ requests for comment.