Hungry brunch-goers were treated to an unpleasant surprise Sunday morning when a mysterious, noxious substance wafted through Ricky’s All Day Grill.

The sudden influx provoked coughing fits in patrons and forced staff and eaters to flee from the Second Avenue eatery.

It started with the kids, said Gordon Hart, who was dining with his wife and cousin when the hacking began.

At different tables in the eatery next to the Days Inn, children were hacking.

“You kind of ignored it,” Hart said today, “but then another person (started coughing) and other person.

“Then it was just everybody – every single person in that building was coughing, except for the staff, who were in and out of the kitchen,” he said.

It was around 11:30 to 11:45 a.m. Hart’s Yukon Big Bite breakfast (three eggs, three strips of maple bacon, ham, sausage, toast and hash browns fried up with peppers and onions) had just arrived.

As his group tucked in to their greasy feast, coughing sounds grew louder and louder.

Then Hart’s table was hit.

By 12:05 p.m., Hart, his wife and his cousin had abandoned their meals – as had the rest of Ricky’s patrons.

“Everyone just evacuated the building,” he said.

Hart estimates there were about 30 diners in the restaurant at the time.

What caused the mass bout of coughing remains a mystery.

Some speculated pepper spray that went off inside the building or nearby, said Jane Bell, who works at the restaurant and is taking over for manager Marilyn Bell (her stepmother) while she’s on vacation.

Bell wasn’t at Ricky’s Sunday morning, but said the staff described feeling itchy throats.

“There was no smell,” she said. “Nobody smelled anything, you couldn’t see anything.” Hart confirmed this.

He said that whatever it was that drifted through the dining room Sunday was odourless, tasteless and didn’t irritate the eyes.

He likened the sensation to an allergic reaction.

“I have summer allergies, it was like that, where you want to sneeze but you can’t get rid of it,” he said.

His wife, who has asthma, got it worse.

“It affected her quite quickly and harshly,” he said, adding that both of them felt fatigued for two to three hours after the fact.

“I’m sure that’s just from coughing so much from an irritant,” he said.

“Your chest gets sore when you cough for four or five minutes straight.”

Ricky’s staff took the bizarre event in stride.

One server attempted to run meals outside to her guests.

“She had, like, six plates, her arms full,” said Hart.

Patrons had the costs of their meals refunded.

The staff waited for all the guests to leave before closing up early, said Bell.

When she came back at around 4 p.m., the irritating substance had dissipated.

“There’s nothing we can really do about it, so we call it a loss and move on,” said Bell.

The Yukon Workers’ Compensation Health and Safety Board is investigating the incident, but can’t yet confirm the substance that caused the coughing, or its source.

Spokesperson Andrew Robulack said the board was contacted by a member of the public who “voiced a great deal of concern” over the event at Ricky’s.

That prompted the investigation.

The concerned citizen is not a Ricky’s employee, he said.

A safety officer from the board visited Ricky’s on Monday, said Robulack.

Yukon government health inspectors have not attended the scene and there is no plan for them to do so, Pat Living, a spokesperson for the Department of Health and Social Services, said today.

As for Hart, he said the incident hasn’t turned him off the spot where he does brunch once or twice a month.

“It’s never going to steer me away; it wasn’t a bad experience. I felt bad for them,” he said.

“The only weird thing for me is I’d like to know what it was.”