The mistake has left people fuming, with scores of Twitter users flooding the OPG’s Twitter feed to share their disgust.

«Someone needs to be held accountable for this,» Andru Valpy wrote.

«This is a completely unacceptable use of the Emergency #Alert System. You had the entire province waking up in fear.»

Another user, Alex, wrote: «Me and probably a couple million people almost had an aneurysm [because] of that msg.»

Amber Waves wrote, «That’s a really major error. People with anxiety disorders woke up to this and their health was impacted, never mind everyone else. Unacceptable. Was there an incident of any kind? Also a tweet isn’t enough — not everyone who got the alert will see Twitter to know it’s all OK.»

One user posted a screen shot from the HBO miniseries Chernobyl,and there were several tweets referencing what happened in Hawaii when a police training exercise in September 2019 set off false hazard alarms on Oahu and Maui, resulting in major public panic.

‘A big time error’

Dan Croft, who grew up in the area, described this morning’s alert as «a big time error,» adding that he’s at a loss as to how it could have happened.

«I was worried at first and, after, when they said it was a mistake I was kind of irritated because that’s a big mistake to send out,» Croft told CBC News.

«I grew up here so it’s always a worry in my mind living around the nuke plant. You think the worst and hopefully good comes out of it.»

Glen Tracy, who has lived in Pickering for 25 years, says this is the first time he’s received an alert about an incident at the plant.

«I was surprised … it got me up in the morning. It’s something I wasn’t expecting,» Tracy told CBC News.

«There’s not much you can do about it anyway. I don’t think there’s anything you can do.»

Erik Norvell said he was caught off guard, but did not panic too much.

«It was a bit confusing, I just wasn’t expecting it,» he told CBC News.

«I wasn’t too worried. The way they worded it didn’t seem like it was that big of an emergency.»

Like Norvell, Wayne Stinson said he was not too concerned.

«I’ve lived beside this plant for 42 years and I’ve had no worries yet, so, I don’t think there’s too much going on,» Stinson told CBC News.

«Everything is normal. I’m still alive. I’m not worried about that plant.»

Pickering mayor demands full investigation

Pickering Mayor Dave Ryan has demanded a full investigation, adding that he was «upset» that the error occurred.

«Like many of you, I was very troubled to have received that emergency alert this morning,» Ryan wrote on Twitter.

«While I am relieved that there was no actual emergency, I am upset that an error such as this occurred. I have spoken to the province, and am demanding that a full investigation take place.»

Toronto Mayor John Tory has also responded to the false alert, calling for a full investigation.

«We still don’t know what the mistake was. Was the mistake that there was some incident that happened that wasn’t an emergency? Was it a mistake in pushing the button as it were?

«I think there are just so many questions that require a complete investigation here,» Tory told CBC News.

Solicitor General Sylvia Jones has since issued a statement saying the alert was issued in error to the public during a routine training exercise being conducted by the Provincial Emergency Operations Centre (PEOC).

«There was no incident at the Pickering Nuclear Generating Station that should have triggered public notification. Nor was there ever any danger to the public or environment,» Jones wrote.

The Pickering station has been operating since 1971, and had been scheduled to be decommissioned this year, but the former Liberal government — and the current Progressive Conservative government — committed to keeping it open until 2024. Decommissioning is now set to start in 2028.

It operates six CANDU reactors, generates 14 per cent of Ontario’s electricity, is responsible for 4,500 jobs across the region and is one of the largest nuclear generating stations in the world, according to OPG.