Families of federal inmates are urging Canada's prison system to end the use of drug scanning devices they say are faulty and unreliable.

Mothers Offering Mutual Support (MOMS), a group whose members have sons and daughters in prison, has filed an electronic petition in Parliament calling on Public Safety Minister Ralph Goodale to review the use of ion scanners and explore more effective alternatives to keep drugs from getting behind bars.

The ion scanners devices are designed to detect trace amounts of particles. Correctional Service Canada has placed these devices in the lobbies and mailrooms of some of its prisons in a bid to reduce the flow of drugs into its facilities.

The devices are extremely sensitive, and MOMS says in its petition that the scanners set off false positive readings at an "alarming" rate.

Anne Cattral, whose son is incarcerated at Ontario's Warkworth Institution, said she has lost count of the times she has tested positive for morphine, hash, opium and heroin. She follows a rigorous regime of washing, cleansing coins and jewelry and driving with plastic gloves before visiting the prison to limit the chances of a false reading.

Cattral said a positive test can lead to the visit being denied. It is also recorded on an offender's file, affecting future private family visits, transfers, and parole, she said.

She says she's been denied entry, and knows others who have been as well.

Anne Cattral, whose son is incarcerated at Ontario's Warkworth Institution, is petitioning the federal government to stop the use of ion scanners as a drug prevention tool. (Andrew Foote/CBC)

"It causes a great deal of stress, because people know it has serious consequences," she told CBC.

Cattral said the Ion Mobility Spectrometry (IMS) devices used by the Correctional Service Canada can pick up trace amounts of prohibited substances through items like cash, credit cards, or even particles in the air.

Family ties key to rehabilitation

"CSC is paying lip service to keeping drugs out by relying on these tests and is destroying relationships and families in the meantime," she said. "Maintaining strong family ties through visits is a very important component in the rehabilitation and reintegration process but the damage caused by this flawed system is counter-productive."

International research posted on CSC's website acknowledges problems with the technology.

Family members of federal inmates have launched an electronic petition to end the use of ion scanners to test for drugs in prisons. (CP)

"One drawback of IMS technology is that it measures drug particulates down to the nanogram, identifying false positives frequently," it reads.

The research notes one study found cocaine was the only drug that was reliably tested while heroin and amphetamine were poorly detected.

"Overall, this review indicates that IMS units are useful in detecting most drugs. However, these devices are often oversensitive and are limited in their ability to detect certain forms of drugs," it concludes.

Risk assessment

CSC spokeswoman Esther Mailhot said ion scanners are one of several tools used to stop the flow of drugs and other contraband into prisons, complementing sniffer dogs, body searches and surveillance.

She said CSC does not collect data on false positives in testing.

"CSC policy requires that a risk assessment be completed following a positive indication on the ion scanner before a decision is made regarding the visitor's request for access to a CSC institution. With these added procedures, there is a low likelihood that visitors be refused entry into a federal penitentiary based on these devices alone," she said.

Ion scanners are typically placed at front entrances or within the mailroom of the penitentiary to detect minute traces of substances.

Samples are collected by wiping or vacuuming objects, then placing the filter or swipe into the unit.

The e-petition to end the use of ion scanners, sponsored by Quebec NDP MP Matthew Dubé, will be open for signatures until April 5, 2017. An electronic petition is open for signatures for 120 days. If it gathers more than 500 signatures, the government is required to respond.