Alta. heavy oil upgrader has toxic gas leak

Alta. heavy oil upgrader has toxic gas leak

Residents northeast of Edmonton were told to stay indoors for nearly five hours Tuesday after toxic hydrogen sulphide leaked at Shell Canada’s (TSX:SHC) heavy oil upgrader.

It was the second leak at Shell’s Scotford plant in five days.

Hydrogen sulphide started leaking from a valve in a hydrogen cracking unit at the plant around 10 a.m.

About 1,400 workers from the plant and surrounding chemical plants were evacuated to safe locations, said Shell spokesman Randy Provencal. There were no injuries, he added.

People in about 120 residences and businesses within a five-kilometre radius of the plant were also called and told to stay indoors until further notice, Provencal said.

“We did the off-site and on-site air monitoring throughout the incident and after the incident and there were no levels of concern detected off-site,” he said.

The leaky unit had to be depressurized and during that time Shell sprayed the unit with water to keep it cool and prevent the hydrogen sulphide, which is highly flammable, from catching fire, he said.

Shell contained the leak around 3:30 p.m. and told residents it was OK to go outside again.

Kathy Radke, whose dairy farm is next to the upgrader, came down to a barricaded road by the plant to see what was happening.

“I don’t feel very safe at all actually. I’ve seen these two incidents in the last four or five days and how we were being contacted and everything, it’s really quite sad. It definitely makes us not very safe around here,” she told Global News.

Another resident said his family had some health problems since the earlier leak.

“We’re not sure what’s really going on,” he said. “We’re getting an awful taste and getting headaches and everything else.”

Davis Sheremata of the Alberta Energy and Utilities Board said it’s not known how much gas escaped throughout the five hours.

Hydrogen sulphide, also called sour gas, smells like rotten eggs.

According to an Alberta government work safe site, the gas is extremely toxic and short-term exposure can cause irritation to the nose, throat, eyes and lungs, while higher concentrations can cause serious health complications and death.

Sheremata said the board is investigating Tuesday’s leak and another one that happened at a different part of the plant last Thursday.

No one was injured in that leak and no sour gas was found outside the plant, he said.

“There have been some concerns expressed to the EUB about the public notification that was done at that time and we’re looking into that,” Sheremata said.

“We had concerns from some people about the way they were notified and from some people that they may not have been notified at all.”

The board approved late last month an expansion of the upgrader to nearly double its capacity.

Provencal said last Thursday’s leak involved flaring of sulphur dioxide gas.

“We did do the shelter-in-place message with our neighbours last week as well, but the call-out wasn’t as successful as we would have hoped it to be, so this time around it did go very smoothly and those folks were communicated to in a timely fashion.”

Provencal apologized to Shell’s neighbours and said “this isn’t something that we want to see happen at our plant site.”

“But I don’t think this is reflective of our operational performance here at the plant site.

“The refinery’s been here for 23 years and the upgrader’s been here for almost four years and we do have a solid track record from an operational perspective and a safety perspective.”

He stressed the two leaks are unrelated.

Shell’s Scotford upgrader processes bitumen from the Alberta oilsands into synthetic crude oil.

It’s part of its Athabasca oilsands operation, which it owns along with Western Oil Sands (TSX:WTO) and Chevron Canada (NYSE:CVX).

In July, Shell announced plans to proceed with an expansion that could cost upwards of $12.8 billion to add an additional 100,000 barrels of daily capacity to the existing 160,000 barrel output.

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