Airport scanners that see through the clothes of travellers have received the blessing of Canada's privacy czar.
Chantal Bernier, the assistant federal privacy commissioner, said Friday the national air security agency has successfully answered her office's questions about the project.
The system, tested in British Columbia at the Kelowna airport, allows a screening officer to see whether someone is carrying plastic explosives or other dangerous items.
The proposal has stirred controversy because the scanner produces a three-dimensional outline of a person's naked body.
"It is a very touchy issue, and we have addressed it with exactly that level of care," Ms. Bernier told a gathering of security officials and academics.
Under the plan approved by the privacy chief, the officer would view the image in a separate room and never see the actual traveller.
Only people singled out for extra screening would be scanned, and they would have the option of getting a physical pat-down instead.
Ms. Bernier said the holographic image generated by the scanner makes it difficult to identify the traveler's face.
"You would not know who it is, even if you knew the person was in line," she said at the annual meeting of the Canadian Association for Security and Intelligence Studies. "We've actually tested it.
"In addition, the image would be deleted the moment the person leaves the screening portal.
"In our view, these privacy safeguards meet the test for the proper reconciliation of public safety and privacy," Ms. Bernier said.
The Canadian Air Transport Security Authority has done thorough threat assessments that reveal a need to search passengers for weapons that might elude a conventional metal detector, she said.
Giving a traveller who undergoes secondary screening the choice of either a full-body scan or a pat-down reduces the "sense of invasion" posed by the new tool, Ms. Bernier added.
In a preliminary assessment early last year, the air-security authority said the scanner project amounted to a "low privacy risk" due to the built-in safeguards.
The scanners are already in use at airports in cities including Amsterdam, Moscow and Phoenix. They are also found in the high-security "green zone" of Baghdad and at some U.S. courthouses and prisons.
The air-security authority says the low-level radio frequency wave emitted by the body scanner meets Canadian health-and-safety standards.
Data from the Kelowna pilot project will help the security authority determine which Canadian airports would most benefit from scanners.
Transport Canada would then decide whether to approve use of the devices across the country.