EDMONTON -- Three deaths at Edmonton's Remand Centre have raised fears of widespread fentanyl abuse.

Alberta Justice officials said Thursday there were three deaths this year at the lockup, but wouldn't confirm they were caused by fentanyl.

"The cause of death isn't released due to privacy considerations for the deceased and his family, or (if) the cause of death hasn't yet been determined," said spokesman Dan Laville in a statement.

Laville confirmed the deaths were on May 14, Sept. 1, and Sept. 9.

CBC reported unnamed sources saying the three cases were overdoses and that the centre is rife with fentanyl abuse.

Alberta Health Services says that from the end of February to the end September there were 23 suspected opioid overdoses at the centre.

It said during that time 23 doses of naloxone -- which blocks or reverses the effects of opioids --were administered by medical staff.

The province is making naloxone more widely available for emergency resuscitation in fentanyl overdose cases.

Alberta Liberal Leader David Swann said the remand centre deaths are a dangerous sign.

"Even in controlled environments, the number of opioid deaths in Alberta is rising. This should ring alarm bells throughout the province," said Swann in a news release.

"I am also frustrated that Albertans are relying on the media to investigate and publish these statistics, rather than our government.

"Alberta health officials have repeatedly stated a public health emergency is not necessary. However, the slow drip of information and regular revelations of new problems indicate the government of Alberta does not have the grip on this crisis it says it does."

There were 159 fentanyl-related deaths in Alberta in the first six months of this year, compared with 139 over the same time period last year.

The problem worsened last week when Karen Grimsrud, Alberta's chief medical officer of health, confirmed that carfentanil was recently found in autopsies of two Alberta men.

Carfentanil is about 100 times more toxic than fentanyl and about 10,000 times more toxic than morphine.

The opioids, even in very small doses, can kill by reducing breathing functions to such a low level, the brain is starved of oxygen.

Mounties have confirmed a cache of carfentanil was seized earlier this year that could have yielded 50 million lethal doses.