Two city employees have been suspended after bringing pot brownies to work, making a co-worker ill after he unknowingly ate one.

City of Hamilton public works head Gerry Davis confirmed that an investigation is underway, and says determining what happened is a high priority.

"We're taking this seriously, and we want to wrap it up as soon as possible," he said. "It's frustrating. We want a safe and healthy work environment for our employees."

The incident happened around 11 p.m. ET on Dec. 22. That's when a 20-year-old man was taken from the Stoney Creek public works yard in a "code four life-threatening situation," said Hamilton paramedic duty officer Ben Roth.

In every group there will be bad apples — and our job is to mitigate that. - Sam Merulla, city councillor

"It was assessed as a serious situation," Roth said.

Canadian Union of Public Employees Local 5167 president Sandra Walker said she couldn't comment on the investigation "for fear of interfering with or affecting the outcome."

"The city often sends an employee home with pay pending any investigation," she said in an email.

Hamilton police also conducted an investigation, said Const. Claus Wagner, but it was concluded without charges. "There was insufficient evidence to lay charges," he said. The worker who got ill is now doing fine and is back at work, Davis said.

Marijuana affects the body differently depending on if it's eaten or smoked. When it's smoked, users get high faster because THC goes directly to the brain — but if someone eats pot, it takes longer to hit them, and tends to slow motor skills in a more intense way.

Dr. Mitchell Levine, with the Centre for Evaluation of Medicines, said it’s extremely unlikely that a person could die from eating marijuana.

"The fear that can occur when you don’t know what’s happening to you can be a total panic attack," Levine said. "The reality is – someone dying from a THC overdose is almost unheard of."

Coun. Sam Merulla, who is also the chair of the public works committee, said that city management is taking "all of the necessary steps" to make sure the people responsible for the incident are being dealt with.

"In every group there will be bad apples — and our job is to mitigate that."

This is the latest in a series of public embarrassments that have dogged the city's beleaguered public works department in recent years. In 2013, the city used video surveillance and GPS records of city vehicles to investigate over two-dozen employees for "neglect of duties, time theft and/or breach of trust."

Then last year, news broke that some public sector garbage collectors in the city work fewer hours than their private sector counterparts.