Health Canada says that the seizure of liquid fentanyl found in Hamilton that was announced last week is not the first in Canada, despite what Hamilton police investigators say.

The national health agency also says Hamilton police knew the drug they had found was fentanyl in the summer, yet they did not release that information to the public until last week.

Local police say they found the drug in a vial during a bust in May of this year. In a press release, police said that the murky liquid was sent away to Health Canada for testing.

"In consultation with various Health Canada labs, and the Royal Canadian Mounted Police, it is believed that this is the only identified seizure of fentanyl in a liquid state within Canada," Hamilton police wrote in a press release last week.

But Health Canada says that is not the case.

"Health Canada's Drug Analysis Service (DAS) has received liquid samples for testing that have been found to contain fentanyl in the past," spokesperson Renelle Briand said in an email.

"The sample in question was sent in a liquid form and DAS identified Fentanyl in that particular liquid sample."

Hamilton police did not immediately respond to questions about why they announced this was likely the first liquid fentanyl seizure in Canada, when that was not the case.

Former opioid addict Nicole and Debbie Bang, the manager of St. Joseph’s Healthcare Womankind addiction service, explain prescription painkiller addiction. 3:57

Health Canada also says that local police were told that what they had found was fentanyl back in July — yet police didn't notify the public about the deadly drug's new appearance on Hamilton's streets until five months later.

"This sample was submitted to the DAS laboratory on June 20, 2016 and a rush request was not identified," Briand said. "On July 8, 2016 DAS contacted the Hamilton Police Services by phone to inform them of the result.

"The certificate of analysis was returned to the submitting officer on July 12, 2016 by Canada Post."

Hamilton police did not immediately respond to interview requests on the issue.

Dr. Norm Buckley, professor and chair of the Department of Anaesthesia at McMaster University's DeGroote School of Medicine, told CBC News that people should be focusing on the concentration of what was found, not the medium it was found in.

"The medium here is not the message," Buckley said. "Whether it's liquid or powder, the issue here is concentration."

The concentration of the liquid police found is not currently known.

An advisory released in August by the Ontario Association of Chiefs of Police warned that 2016 has been a record year for overdose alerts and seizures of bootleg fentanyl. That refers to drugs that are not prescribed by doctors, but produced synthetically and sold on the black market, usually mixed in with other substances.

As the danger has mounted, so too have the deaths.

In 2005, 18 people died of opioid toxicity in Hamilton. That number peaked at 34 in 2011, and continues to stay high at 31 in 2014.

By contrast, 18 people died in traffic fatalities in Hamilton that year.

adam.carter@cbc.ca