NORTHERN BRUCE PENINSULA, ONT.—Ontario Provincial Police say suspected carbon monoxide poisoning symptoms among a group of vacationers last weekend turned out to be the effects of consuming too many marijuana brownies.

Provincial police Const. Adam Belanger says officers were called to a cottage in Northern Bruce Peninsula, Ont., early on Saturday morning after a number of people renting the home reported feeling sick for unknown reasons.

He says the symptoms initially suggested there might have been a carbon monoxide leak in the cottage, but testing from the fire department quashed that theory.

Belanger says officers then learned that one of the vacationers had baked a pot-laced “brownie cake.”

Of the 10 people renting the cottage, he says only those who indulged in the dessert were feeling sick.

Police did not lay any charges.

“This is the first incident that we’ve had up on the Bruce Peninsula, but with the legalization of marijuana coming up, it could possibly be something that we run into more often,” Belanger said.