A national lobby group is pushing for the disbandment of transit police after obtaining documents that allegedly show an officer left an explosive device on a commercial plane in 2011 as part of a dog training exercise.

The Canadian Taxpayers Federation said it also learned through a Freedom of Information Act request that the officer did not know the device was missing for two days.

Jordan Bateman, CTF spokesman, said by the time the transit officer brought up the missing explosive with superiors, the Air Canada plane had returned to Toronto and was back in service.

Air Canada allegedly inspected the plane 14 times in Toronto to make sure the explosive was no longer on the plane, according to the CTF.

The incident never went public, but FOI records show transit police prepared a news release with the blessing of Transport Canada and YVR, the CTF said.

A transit police spokeswoman denied that anybody on the flight was at risk, as the device could not have exploded without the help of a blasting cap – which was not attached.

She said the device, which looks like a small plastic box with two sticks of chewed gum inside, is only explosive when mixed with other substances.

Transit police dogs must be trained to national standards set by RCMP, she said, which is why the officer was training the dog on an in-service plane, but officers now use a stationary training plane at the BC Institute of Technology.

The officer involved in the incident resigned shortly afterward, she confirmed.

Bateman alleged the mistake cost taxpayers tens of thousands of dollars.

With files from The Canadian Press