Next month, the CTA will begin scanning commuters for explosives using equipment that can detect whether someone is carrying a bomb or has been exposed to bomb-making materials, officials said Friday morning. View Full Caption DNAinfo/Josh McGhee

DOWNTOWN — The CTA plans to begin scanning commuters for explosives using equipment that can detect whether someone is carrying a bomb or has been exposed to bomb-making materials, officials said Friday morning.

The federally funded initiative will be rolled out at Downtown "L" stations, but eventually may be expanded elsewhere in the city, said Nancy Lipman, commander of the Chicago Police Department's Public Transportation Unit.

Riders will start getting screened the week of Nov. 3. Commuters will be selected randomly for the checks, Lipman said.

Initially, the program will target one station at a time, and four or five Chicago police officers will perform the tests, police said.

Federally funded anti-terrorist initiative will use devices known as Mobil Explosive Screening Tools to screen customers for explosives. View Full Caption DNAinfo/Mauricio Pena

Riders' bags or other items will be swabbed with a small cloth, and the cloth will then be inserted into machines known as Mobile Explosive Screening Tools, which can detect explosive compounds.

"The baggage-screening process is noninvasive, takes a very short amount time and will be done in an open area prior to the customer entering the turnstiles," Lipman said.

"The process takes less than a minute, and we expect it to have no impact on riders," said Lipman.

Customers who refuse the screening will be denied access to the transit system, she said.

Commuter Michelle Pike, 34, was unfazed by the announcement.

"Seems worth it," she said. "It's similar to what they do at the airport. I have no negative thought if they are implementing these measures to deter people from harming others."

Janie Urbank, 65, who rides the "L" daily, said it's hard to complain about the measure if it will create a safer commute, even if that means delays.

Other commuters were skeptical that the initiative will have an impact on commuters' safety.

"I guess it gives people more peace of mind, but in all honesty, if someone wanted to do something, they're going to find a way," said Matt Forester, 26. "There's some terrorist groups who have used peroxide bombs that aren't detectable. This [new plan] is not foolproof."

Savannah Klunder, 30, agreed with Forester about the new measure.

"If someone wants do damage, they're going to do it," Klunder said. "I don't think it will keep people safe. This is just going to cause delays."

A customer attempting to enter the transit system after refusing the screening may be subject to arrest, said Adam Paulsen, a police officer and intelligence analyst.

If a positive result is found during a screening, police will then try to determine the reason for it. According to Lipman, the rate of false positives is low.

Both police and the CTA called the initiative an important proactive safety measure. The same screening process has been implemented in transit systems in New York, Boston, Washington, D.C., Los Angeles and Union Station in Chicago, Lipman said.

"Other cities are doing [these searches] similarly, except for Los Angeles," said Paulsen. "They physically go into the bag. We decided to stay away from that. We figured this was the best and most effective way to conduct our operations here."

Lipman explained that although "there is no known terrorist threat to the Chicago’s transportation system, we're adding this as another protective measure to best ensure the safety of transit riders."

The number and location of stations screened on a given day will be picked at random to serve as a deterrent, Lipman said.

However, there will be signs on display to explain the initiative being carried out for the day so customers aren't completely off guard, Lipman added

CTA Chief of Security Jim Keating described the new program as a "good homeland security initiative."

"It's going to take 20 or 30 seconds of a commuters' time, while we know the commuters' time is precious but we think their safety is priceless," Lipman added.

At the moment, the program has three mobile screening devices available.

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