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Problems with Ion Scanners Used to Detect Drugs on Prison Visitors

by Ed Lyon

Ion scanners were initially installed in prisons in the early 1990s to detect controlled substances on visitors, whose hands and clothes are typically swabbed for testing. But visitors and prison staff who filed lawsuits – in states including New York, Massachusetts and Maryland – claimed they were penalized by false alarms from the machines. 

Ion scanners are able to detect trace amounts of illegal substances as low as 0.01 nanograms, or 1/100 billionth of a gram – an amount smaller than a single grain of refined sugar, and completely invisible to the naked eye. The lawsuits claimed that even accidental or incidental contact with drugs – such as touching currency with trace drug residue – could trigger the scanners. The suits also argued the machines could not distinguish whether a trace amount of a substance was used in a legal product or an illegal drug.

While insisting the scanners are technically accurate, Jennifer Verkouteren, a scientist with the National Institute of Standards and Technology’s Surface and Trace Chemical Analysis Group, which is part of the U.S. Department of Commerce, admitted they are not perfect at distinguishing compounds used in both illicit drugs and legal products.

“It’s hard to make that technology proof against the universe of compounds people can put on themselves, and that might then get introduced as an environmental contaminant into the [scanner],” Verkouteren said.

As a result, people have complained of false positives when ion scanners alert to illegal methamphetamine rather than common over-the-counter medications that employ two of its component chemicals, lidocaine and benzocaine – which are the active ingredients in treatments for cold sores, denture irritation, hemorrhoids, ingrown toenails, orthodontic pain, skin irritations, sore throats, swimmer’s ear, sunburn and toothaches. Even some condoms contain those chemicals.

Another complaint about ion scanners involves secondary transfer of an illegal substance that the person being tested has never used or handled. With studies showing that 80 percent of U.S. currency has been handled by someone who has had direct contact with cocaine, there is up to a 90 percent probability that anyone who has touched currency will test positive for cocaine when passing through an ion scanner – even after thorough hand washing.

In 2017, the Pennsylvania Department of Corrections (PDOC) used $1.86 million of a $15 million earmark to fight illegal drugs in state prisons to begin upgrading its ion scanners to the Rapiscan Itemiser 3E series. PDOC’s old scanners, in use since the 1990s, could not keep up as the makers of synthetic marijuana – known as K2 or spice – continually changed one or two chemical components to stay ahead of legislative bans. The new scanners can be updated to detect variants of K2. 

The scanners do not alarm on a false positive, “ claimed PDOC spokesperson Amy Worden. “They alarm to a programmed known substance. If that substance is detected, the machine will alarm. The department sets threshold levels of substances to rule out any incidental contact with substances that an individual may have had during normal daily routines.”

However, a professor of criminology at Wilfrid Laurier University in Ontario who has studied the use of ion scanners disagreed. Stacey Hannem noted that research has discovered the machine’s alarm for opiates can be set off by some detergents or even poppy seeds.

I’ve heard stories of guys inside [prison] who will tell their family, ‘It’s too stressful, don’t come,’ because their mom’s or wife’s rings set off the ion scanner, and it can be scary and traumatic,” she said.

Yet contact with family and friends is an extremely important factor in a prisoner’s successful reintegration into society when released, with one study showing a 13 percent reduction in recidivism rates for offenders who received regular visits. 

If we want people to do well on the outside,” Hannem added, “we need them to be able to maintain those relationships.”

In order to keep from setting off ion scanners, some Pennsylvania visitors keep their visitation clothing in air-tight plastic bags after having them specially laundered. Once at the prison, they vigorously scrub their identification cards and car keys with a bar of soap in the restrooms in the prison’s anteroom or lobby, and try not to touch anything until scanned.

How can we get around touching anything else once we’ve washed our hands?” J-Nae Kettoman said she asked herself when visiting her husband, who is serving 10 to 20 years at SCI Phoenix.

In 2018, Kettoman twice set off the prison’s ion scanner. Because there was no backup test to disprove her claim that the readings were false positives, a third alarm within a six-month period would have suspended her visitation privileges for 180 days. 

Attorney Angus Love with the Pennsylvania Institutional Law Project recalled that the first day the ion scanners were introduced into state prisons in the mid-1990s, he received a call from an 87-year-old grandmother who tested positive for the party drug ecstasy.

“She was like, ‘I don’t even know what ecstasy is,’” Angus said.

It was that complaint which led the PDOC to adjust its machines to a higher threshold for illicit substances. But the upgraded machines have triggered a new wave of complaints from prison visitors, such as Rebecca Mitchell. The 73-year-old member of the Pennsylvania Prison Society’s Official Visitor program has now stopped taking her antidepressant medications on visitation days, even though she had a note from her doctor explaining the drugs could set off the scanners.

“But one of the prisons would not honor my doctor’s letter,” she said. “It was embarrassing and frustrating, because the prisoners don’t get the visit, and the prisoners [may then be] monitored for drugs.” 

PDOC spokesperson Worden said a doctor must provide a written prescription, not just a note. The prison system’s policy allows any visitor who sets off an alarm once to wash their hands and try again. Failing the second attempt means a non-contact visit through a glass barrier. But subsequent alarms can trigger a suspension of visitation privileges, from 180 days for a third alarm within a year up to “indefinitely” after the fifth. 

Dana Cooper wasn’t able to visit her husband at SCI Phoenix after she set off three scanner alarms within a year following the arrival of the new machines in mid-2017. She lost her visitation privileges – unfairly, she insists – though she had never set off the old scanners.

“I don’t drink. I don’t do drugs. I don’t smoke,” Cooper said. “People don’t realize the effect the ion scanner has on visitors, inmate families, marriages.”

Antoinette Haren visited her husband at SCI Phoenix for seven years without a problem until the new scanners were installed. After the first alarm, she scrubbed her hands and used hand sanitizer.

“But the guards were saying the ion scanner will pick it up as a drug,” she said. “So I’m like, ‘Let me get this straight: You have a machine that will pick up hand sanitizer as a drug? And you know of this?’”

She now arrives for visits without perfume or makeup, carrying her own soap to wash her hands, ID and the key to her locker, trying not to touch even a doorknob. Yet she set off another alarm in mid-2018, which was her third within a year, so her visitation privileges were suspended for 180 days.

California decided against deploying ion scanners after a three-year study period. And Canada’s Office of the Correctional Investigator reported to Canadian lawmakers that “these machines can be oversensitive and unreliable, and often produce what are known as ‘false-positive’ reports.” But many states still use them, as does the federal Bureau of Prisons despite a temporary suspension in federal prisons in 2009. [See: PLN, May 2010, p.30; Feb. 2009, p.11].

As for litigation challenging the use of ion scanners, one lawsuit was filed by prison employees at the Maryland Correctional Training Center, who were subjected to “strip and visual body cavity” searches and searches of their cars by a drug dog after they set off a scanner. No drugs were found. They were also required to submit to a urine test. All passed.
The employees alleged that they were not allowed to explain how they might have innocently come into contact with trace amount of drugs, and that the strip and car searches were performed even if the amount of drugs detected was miniscule. They filed a civil rights lawsuit pursuant to 42 U.S.C. § 1983 in 2009. The defendant prison officials moved for summary judgment, which was granted by the district court.

On appeal, the Fourth Circuit held the defendants were entitled to qualified immunity because there was no clearly established federal law that would make them believe a positive indication of drugs from an ion scanner did not constitute reasonable suspicion to conduct more intrusive searches consistent with the Fourth Amendment. The appellate court noted that the only courts which had reviewed the use of ion scanners had concluded they were a reliable method of detecting drugs. 

Although it specifically did not hold that a positive scanner result will always justify a strip search, the Court of Appeals found it was not clearly established that positive ion scanner results could not justify a strip search. Thus, the defendants were entitled to qualified immunity and the judgment of the district court was affirmed. See: Braun v. Maynard, 652 F.3d 557 (4th Cir. 2011). 


Sources: Philadelphia Inquirer,,,

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Related legal case

Braun v. Maynard