According to Airdrie Fire Chief Kevin Weinberger, an old valve on a well owned by Calgary’s Toro Oil & Gas Ltd. in the Dry Creek Bay area in southwest Airdrie failed at 6:30 p.m. on Nov. 22, causing the release of sour gas that was smelled in Airdrie, Rocky View County and as far away as northwest Calgary.
“A valve on a well head failed,” Weinberger said. “It sounds like, from talking to Toro, that it was an old valve and they don’t know why it failed. It just failed. Fifteen people from nine homes were evacuated for less than 24 hours.”
The Airdrie Fire Department received a 911 call from a resident who was alerted to the leak by the noise.
“It sounded like a jet engine because (the sour gas) was coming out at 11,000 pounds per square inch at the well head so it was very noisy,” Weinberger said. “Then the odour followed. We had a lot of calls as the evening went on from northwest Calgary as well.”
An Alberta Emergency Alert was issued at 10:58 p.m. on Nov. 22 advising residents of southwest Airdrie, north Rocky View County and northwest Calgary to avoid the area around Yankee Valley Boulevard and 24 Street.
Weinberger said 24 Street south of Yankee Valley Boulevard was closed while the alert was in effect.
The alert was cancelled at 1:16 p.m. on Nov. 23.
“It was a public nuisance because of the smell, the odour of the petroleum that was venting off,” Weinberger said. “But according to (Toro’s) updates, there was never any risk to public safety.”
“The risk for us was if it would have lit up, because of the volume (of sour gas) that was being pumped out of there. Because of the pressure, it would have been a very big flame.”
Firefighters shut down all gas and power to the evacuated homes to limit the ignition sources should the leak turn into a fire, according to the Fire Chief.
Weinberger said residents were allowed back in their homes at 3 p.m. on Nov. 23.
“Our firefighters, FortisAlberta and ATCO Gas restarted all the homes and reignited all the power,” he said. “Then we did our monitor readings and then let people back in.”
Evacuated residents were taken to the Best Western Hotel in Airdrie and given rooms, according to Weinberger, with Toro picking up the bill.
A total of 15 firefighters from the AFD responded to the scene, as well as three trucks and two command units. Weinberger said he put the Crossfield Fire Department on standby while the Airdrie crews were tied up working with staff from Toro to contain the leak.
According to Weinberger, the well was part of a decommissioned line, meaning Toro was preparing to fill it in. The cause of the leak is still under investigation.
