OTTAWA -- Screeners at the Edmonton airport failed to identify, intercept and handle a pipe bomb in "the manner expected" by Canada's air security authority, says an internal review.

Several personnel had feelings -- with varying degrees of conviction -- that the item discovered in a teenager's carry-on baggage might be a pipe bomb or some other kind of improvised explosive device, the newly disclosed review found.

However, because a Canadian Air Transport Security Authority manager believed the item was simply drug paraphernalia, no one acted fully on the suspicions, and the police were not called until several days later.

"Despite the best efforts of a competent, dedicated, and diverse group of screening personnel, CATSA failed to identify a pipe bomb/IED," the report says.

"This incident has provided an excellent opportunity for CATSA to self-examine, learn and grow."

The air security authority's report on the September 2013 episode, completed last November, was obtained Thursday by The Canadian Press under the Access to Information Act.

The review recommended improvements to training, search techniques, decision-making and clarity of employee roles.

Skylar Murphy, who had built the pipe bomb with a friend for their own amusement, inadvertently left the device in a camera bag and forgot about it.

Murphy, of Spruce Grove, Alta., was 19 when he pleaded guilty last December to possession of an explosive device. He was sentenced to one year probation, fined $100 and ordered to make an in-person donation of $500 to the University of Alberta Hospital's burn unit.

In the early morning of Sept. 20, an X-ray operator at the airport noted an unusual, barbell-shaped metallic object and requested a physical search, the report says.

A screening officer found the approximately six-inch metal pipe -- which had end caps and was wrapped in wire -- in a cloth bag marked with a smoke shop insignia.

The screening officer was "unsure whether or not the item was permitted" and consulted a checkpoint manager who, based on a "very quick visual check," decided it could be taken through security, the review says.

The officer then tried to return the item to the passenger, who had become nervous during the screening process, indicated the item was not his, and ultimately forfeited it to the officer.

Several hours later the item was examined by other screening officers who felt it could be a bomb and revisited the issue with the checkpoint manager. The manager unscrewed one end and dumped out some of the flaky contents into a garbage can, but "remained convinced" the item was drug-related.

The item sat in an office over the weekend until, after further reflection, the air authority contacted the RCMP.

"Although screening officers in Edmonton ultimately prevented a viable pipe bomb from being introduced onto an aircraft, the item was not identified, intercepted, or handled in the manner expected by CATSA," the report says.

The screening officer who searched the bag told the reviewers that "alarm bells" were going off inside his head when he first found the item, and that he got "bad vibes" from the situation.

"However, he did not follow his gut instinct, and rather deferred to the (checkpoint manager)."

More than one employee was suspended and received mandatory retraining, air security authority spokesman Mathieu Larocque said Thursday. He declined to provide further details.

After the incident, the air authority distributed relevant bulletins to screeners, and modified training materials with a "stronger emphasis on detecting potential explosive devices" and the proper protocol to follow in the event one is found.

The agency also moved to ensure screening officers have time to analyze travellers' items and make the proper call, Larocque added.

"The idea is to give the screening officer all the confidence that they need to make these decisions."