Saskatchewan’s Ministry of Energy and Resources says it continues to oversee cleanup efforts at Cenovus Energy’s Rush Lake thermal site.
In a statement, the ministry said it’s working with Cenovus to manage the incident, isolate the cause and ensure public and environmental safety.
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According to Cenovus, the over two-week-old release is mostly water vapour.
The company also stated that the vapour can smell like rotten eggs due to the presence of hydrogen sulphide (H₂S), a gas that can be toxic in high amounts. However, both Cenovus and the province state that air quality tests indicate there is no current risk to the public or wildlife.
“Our testing indicates that while the H₂S levels may be detectable as an odour, they are not considered to represent a health concern,” Cenovus said in a May 21 update.
The Ministry confirmed on May 23 that it approved temporary flaring at the facility. That work helps purge gas from flow lines and equipment. Ministry drones are monitoring air quality in and around the site.
“From day one of the incident, Cenovus has been in contact with many homes in the area as well as First Nations communities,” said the Ministry, noting a community phone line is open 24/7 for any concerns at 1-877-697-4480.
Minister of Energy and Resources Colleen Young stated that the province will continue to prioritize safety.
“As the provincial oil and gas regulator, we will continue to make public and environmental safety the ministry’s top priorities as we manage the response to this incident,” said Young. “Working with Cenovus, we are committed to ensuring we understand all impacts associated with this incident.”
Cenovus says it’s continuing to monitor the site with fixed and mobile air testing. The company also says there is no sign of harm to nearby water bodies or wildlife. Testing, however, continues out of caution.
Berms remain in place around the site and more staff are working to carry out the response plan.
Online complaints from numerous residents in the surrounding area note strong smells of rotten eggs.
Asking an expert
Environmental scientist Dr. Tariq Siddique said even small releases can carry risk depending on exactly what is leaking into the environment.
“Hydrogen sulphide is a toxic gas,” said Siddique, a professor at the University of Alberta. “Depending upon the nature of release, the other materials might be crude oil that comes with brine solution containing salts and trace metals.”
Siddique says oil contains hundreds of hydrocarbons, each of which spreads and affects soil and water in different ways.
“Toxic hydrogen sulphide can affect the nearby community while hydrocarbon contamination in soil and groundwater will have a lasting effect,” he said.
According to Siddique, in cases like this, hydrocarbons and brine could seep into groundwater. Lighter hydrocarbons like BTEX are especially toxic and more likely to move into water.
Meanwhile, Cenovus is still unsure of the amount of material involved and exactly what they are. They continue to restrict access to the site and surrounding area.
The Ministry stated that its staff will continue to attend regular updates and work with Cenovus, remaining involved as cleanup and investigation work progresses.
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