More than 20 people, many of them children who were attending an art camp, had to be hospitalized after the gas leak at the Robert McLaughlin Gallery.
Henry said that by Monday, all of Oshawa's public spaces, including art galleries, libraries and arenas, will be equipped with carbon monoxide detectors.
"I'm not sure there will be any left to buy in Oshawa come the end of tomorrow, but I can tell you as of Monday in Oshawa, all our public spaces will be dealt with," he said.
Safety regulations require all public spaces in Ontario to have smoke detectors, but they are not required to have carbon monoxide detectors.
Despite his quick call for action, the mayor said he's baffled by the incident because the building's heating and cooling system has been checked twice recently.
Stephanie Gratton's five- and six-year-old children were at the art camp. They were both sent to hospital Friday where they received oxygen for five hours.
"I was terrified. I was just really upset. And more upset for my kids, because they were sick and ill," said Gratton
Gratton's son had a headache, nausea and dizziness.
She says this scare could have been avoided even without a detector; she says she alerted camp staff Thursday and again Friday morning of a gas smell.
"They said it's the maintenance room, everything is fine. That's what I was told. So I left my kids," said Gratton.
Neither the mayor nor top gallery staff knew about the smell complaint, but they said they will investigate.
"I'm a mom too, I would totally be upset. However, I did not hear about the complaint," said Gallery official Olinda Casimiro.
The mayor pointed out that carbon monoxide gas can be odourless.
"If they smelled something around the downtown core - there's a number of restaurants - there could have been a smell here, but carbon monoxide is odorless."
For Gratton the damage is done.. Her kids were supposed to go back to the camp Monday, but she said she doesn't feel like it's safe.