His remarks came in a press conference at the Orlando area’s Sanford Airport.

Mica said this week the newly enacted Federal Aviation Administration Modernization and Reform Act should streamline the process for airports that want to contract with private security screening firms instead of relying on Transportation Security Administration run screening.

The Winter Park Republican said that, in the decade since it was created, the TSA has ballooned into a “mammoth agency that attempts to intimidate small airports that are efficiently run.”

He said switching the 35 top airports in the nation to private security screening would save tax payers one billion dollars over the next five years.

Mica said the TSA rejected some airports which applied to contract with private security because it said that would cost more.

But he said the agency’s reasoning was not backed up by a Government Accountability Office report.

“GAO said that TSA cooked the books, that they added costs in,” he said.

Sixteen of the nation’s 457 airports currently run private security screening,  and there are others that want to do the same, like Orlando Sanford International Airport.

Sanford already tried to opt out of all-federal transportation screening, but was rejected by the TSA last year.

The airport’s president, Larry  Dale,  said opting out of TSA run screening is about more than saving money.

“We’re already responsible for security here,” Dale said.  “If things screw up we get the blame. We want to have a part and a say in the security of this airport.”

Airports which opt out of all-federal screening will get to choose who screens their passengers, but security firms would still have to meet federal approval and operate under TSA guidelines.

Sanford could hire its own agents to run security screening, but it’s more likely to contract with a private firm.

“We’re not going to go out and do it ourselves like Jackson Hole (Wyoming) does, as a much smaller airport,” Dale said.

Sanford has reapplied to opt out, and Dale hopes to have an answer from the TSA within months.

DC Metro Station (photo by Jill Robidoux)

TN’s Andrea Bernstein talks about the House’s transit cuts on this morning’s Brian Lehrer Show. (WNYC)

A New York Times editorial provides a “brief and by no means exhaustive list of the (transportation) bill’s many defects“; calls it “uniquely terrible.” (New York Times)

And: NYT critic: move Madison Square Garden to far west side to fix Penn Station. (New York Times)

A TSA program that pre-clears passengers –and lets them keep their shoes on while being screened by airport security — is being expanded to more airports. (Star-Ledger, The Hill)

California labor groups are running ads that hammer home U.S. DOT head Ray LaHood’s message that high-speed rail=jobs. (Sacramento Bee)

Pennsylvania’s governor didn’t budget for transportation because its problems are too overwhelming. “This is not a budget item. It is too large for that. Transportation must be confronted as its own distinct and separate topic.” (Philadelphia Inquirer)

A German carpooling website plans to enter the U.S. market. “We think all trips by car could be shared,” says the founder. “Whenever you want to go with your car, you could take people with you, and therefore reduce carbon emissions and your costs.” Everybody say Mitfahrgelegenheit! (The World)

The four consortiums picked to bid on New York’s Tappan Zee Bridge rebuild include some of the world’s most successful construction companies — and some with histories of delays and millions of dollars in cost overruns. (Journal News)

Why is there an uptick of cracked rails on the DC Metro? (Washington Post)

A pair of lawmakers from New York and New Jersey are pushing legislation to roll back last summer’s Port Authority toll and fare hikes. (Star-Ledger)

Manhattan’s Hudson Square neighborhood sees bike boom, installs more racks. (DNA Info)

Megabus is moving its Manhattan pickup site — and doesn’t have to pay rent. (DNA Info)

A map that replaces London Underground station names with anagrams is getting second life. You can get from Arcadian Noodle to Satan Dew, and you don’t even have to transfer at Mind Eel!

The TSA testing new scanning technology at McCarrin Interational Airport in Las Vegas. (Photo by Ethan Miller/Getty Images)

(Michael Grabell, ProPublica) Sen. Susan Collins, the top Republican on the homeland security committee, plans to introduce a bill in the coming days that would require a new health study of the X-ray body scanners used to screen airline passengers nationwide.

The Transportation Security Administration began using the machines for routine screening in 2009 and sped up deployment after the so-called underwear bomber tried to blow up a plane on Christmas Day of that year.

But the X-ray scanners have caused concerns because they emit low levels of ionizing radiation, a form of energy that has been shown to damage DNA and mutate genes, potentially leading to cancer. ProPublica and PBS NewsHour reported in November that the TSA had glossed over cancer concerns. Studies suggested that six or 100 airline passengers each year could develop cancer from the machines.

Shortly after our report, the European Union separately announced that it would prohibit X-ray body scanners at its airports for the time being “in order not to risk jeopardizing citizens’ health and safety.”

The new bill drafted by Collins would require the TSA to choose an independent laboratory to measure the radiation emitted by a scanner currently in use at an airport checkpoint. The peer-reviewed study, to be submitted to Congress, would also evaluate the safety mechanisms on the machine and determine whether there are any biological signs of cellular damage caused by the scans.

In addition, the bill would require the TSA to place prominent signs at the start of checkpoint lines informing travelers that they can request a physical pat-down instead of going through the scanner. Right now, the TSA has signs in front of the machines noting that passengers can opt out. But the signs mostly highlight the images created rather than possible health risks.

The bill is the latest volley in a back-and-forth between Collins and the TSA. At a hearing in November, TSA administrator John Pistole agreedto a request from Sen. Collins to conduct a new independent health study.

But a week later at another hearing, Pistole backed off the commitment citing a yet-to-be-released report on the machines by the Department of Homeland Security’s inspector general.

“I have urged TSA to move toward only radiation-free screening technology,” Collins said in a statement to ProPublica. “In the meantime, an independent study is needed to protect the public and to determine what technology is worthy of taxpayer dollars.”

The TSA uses two types of body scanners to screen passengers for explosives. The X-ray machines, known as backscatters, look like two refrigerator-size blue boxes and are used at Los Angeles, Chicago O’Hare, New York’s John F. Kennedy, and elsewhere. The other machine, which looks like a round glass booth, uses electromagnetic waves that have not been linked to any adverse health effects. Those machines are used at airports in Dallas and Atlanta, among others.

The TSA says the radiation from the X-ray machines is minute, equivalent to that received in two minutes of flying at altitude. That measurement has been verified in previous tests by the Food and Drug Administration, the Johns Hopkins University Applied Physics Laboratory and the Army Public Health Command.

“All the previous independent testing showed that the machines are well below the national standard,” TSA spokesman Greg Soule said.

A group of vocal critics, primarily based at the University of California, San Francisco, has cast doubt on those tests, suggesting that the device used to measure the radiation isn’t equipped to provide accurate measurements on body scanners, among other flaws.

While not commenting specifically on the drafted legislation, Soule said, “the TSA is committed to working with Congress to explore options for an additional study to further prove these machines are safe for all passengers.”

The spokeswoman, Moira Bagley, said Paul set off the machine “on a glitch.” She said Paul was detained after refusing a full-body pat-down following the alarm. Paul is a staunch critic of the TSA in general and pat-downs in particular, calling them a violation of constitutionally-protected civil liberties.

“That don’t fly,” Bagley stated in an email. She said Paul put in a direct call to TSA chief John Pistole, whom Paul has fiercely criticized in writings, speeches and Capitol Hill hearings.

TSA officials denied that Paul had been detained.  “Passengers who refuse to complete the screening process cannot be granted access to the secure area,” a TSA spokesman said.

It was immediately unclear whether Paul was free to proceed or whether the agency was using a differed definition of the word than the was the senator’s staff.

Rep. Ron Paul (R-Tex.), the senator’s father and  a Republican presidential candidate, posted messages on his Facebook page and Twitter feed stating his son had been “detained”.

“There was an ‘anomaly’ in Rand’s initial body scan, so my son requested to be scanned a second time. TSA demands a full body pat down and Rand refused,” stated a post on Ron Paul’s Facebook page.

The TSA issued a statement denying Sen Paul was detained, but saying instead he was denied access to the terminal because passengers who refuse security screening are not allowed to proceed.

Sen Paul was scheduled to speech at the annual March for Life anti-abortion rally in Washington Monday.

UPDATE: Bagley confirms to TN that Sen Paul rebooked on another flight, was rescreened without incident and went on his way without incident. “He’s heading to DC,” she said.

Bagley would not say what further steps Sen Paul may take in the wake of the incident. “Weird how the anomaly disappeared during the same screening process,” she said.

Follow Todd Zwillich on Twitter @toddzwillich

A Transportation Security Administration volunteer demonstrates a full-body scanner at O'Hare International Airport on March 15, 2010 in Chicago. (Scott Olson/Getty Images)

(Michael Grabell, ProPublica) This is part of our year-end series, looking at where things stand in each of our major investigations.

It has become routine for airline passengers across the country: Instead of walking through a metal detector, they now step into a body scanner, hold their arms over their heads and wait until a machine peers through their clothing to make sure they’re not hiding explosives.

The Transportation Security Administration has deployed more than 500 of the body scanners, which they call “advanced imaging technology.” And the agency plans to install them at nearly every security lane by 2014.

The TSA has insisted that the new scanners present “no health or safety concerns for any passenger.” The agency has said they have been used around the world. And it has reiterated that the machines were evaluated by the Food and Drug Administration, leading many to believe that one of the government’s top safety regulators approved the technology.

But a ProPublica/PBS NewsHour investigation this year detailed how the TSA had glossed over cancer concerns about one kind of scanner that uses X-rays. In independent, peer-reviewed studies, radiation experts concluded that the X-ray scanner could cause six to 100 airline passengers each year to develop cancer. Outside the United States, few countries use X-ray imaging machines, also known as backscatters, in their airports. And the FDA has no authority to approve body scanners before they are sold because they are electronic products, not medical devices.

In 1998, an FDA advisory panel recommended a federal safety standard for the X-ray scanners. But the agency decided to go with a voluntary standard set by an industry group made up mostly of manufacturers and government agencies that wanted to use the machine.

In November, the European Union decided to prohibit X-ray body scanners in European airports. In the United States, members of Congress have pushed the TSA to conduct a new, independent safety review. And in Florida earlier this month, Broward County commissioners voted [6] to demand the TSA prove that the X-ray imagers at Fort Lauderdale-Hollywood International Airport are safe.

The TSA uses two types of body scanners:

• The backscatter X-ray machine looks like two blue boxes and is used at major airports, such as Los Angeles, Chicago O’Hare and John F. Kennedy in New York.
• The millimeter-wave machine looks like a round glass booth and is used at hubs such as Atlanta, Dallas-Fort Worth and San Francisco.

The X-ray scanner emits extremely low levels of ionizing radiation, a form of energy that strips electrons from atoms and damages DNA, potential leading to cancer. That risk, although small, has led some prominent scientists to ask why the TSA doesn’t use just the millimeter-wave scanner, which uses low-powered electromagnetic waves that have not been linked to adverse health effects.

The TSA has said that keeping both technologies in play encourages the manufacturers to improve detection capability while lowering the cost for the taxpayer. The agency says the X-ray machine is safe because the radiation is equivalent to the amount passengers receive in two minutes of flying at altitude.

But ProPublica found some potential problems with the millimeter-wave scanner. Several other countries have reported a high rate of false alarms caused by innocuous things, such as folds in clothing, buttons and even sweat.

Other studies and a congressman briefed on classified tests have suggested the scanners could miss carefully concealed plastic explosives like the weapon used by the underwear bomber on Christmas Day 2009.

As Congress continues to debate the safety and quality of the body scanners, government investigators are set to release two important reports in the new year. The inspector general of the Department of Homeland Security is evaluating how well the TSA is monitoring the radiation of the backscatters. Meanwhile, the Government Accountability Office is wrapping up an investigation of the machines’ detection capability, the results of which are likely to be classified.

(Michael Grabell, ProPublica) It was the end of a four-hour congressional hearing, and Florida Rep. John Mica was fuming at Transportation Security Administration officials.

The TSA had begun deploying hundreds of body scanners [1] to prevent suicide bombers from smuggling explosives onto planes. But Mica, the Republican chairman of the House Transportation Committee, had asked the Government Accountability Office to test the machines. The results, he said, showed the equipment is “badly flawed” and “can be subverted.”

“I’ve had it tested, and to me it’s not acceptable,” Mica said at the hearing earlier this year. “If we could reveal the failure rate, the American public would be outraged.”

Mica’s comments received almost no press coverage. But his outrage, together with other reports by government inspectors and outside researchers, raise the disturbing possibility that body scanners are performing far less well than the TSA contends.

The issue is difficult to assess since the government classifies the detection rates of the devices, saying it doesn’t want to give terrorists a sense of their chances of beating the system.

But the evidence is mounting.

Just last week, Department of Homeland Security investigators reported that they had “identified vulnerabilities [2]” in the scanners’ detection capability, though the specifics remain classified. Previous research cast doubt on whether the scanners, which are designed to see underneath clothing, would detect a carefully concealed plastic explosive like the one used by the underwear bomber on Christmas Day 2009. One study suggests the $170,000 scanners would likely miss some explosives that could be found during a pat-down.

And recently, Mica and other members of Congress were briefed by the GAO on the full findings of its covert tests. The results, Mica told ProPublica, are “embarrassing.”

Other lawmakers who have also been briefed declined to comment.

How effective the machines are at thwarting terrorism is critical for evaluating whether the TSA is making airline passengers more secure or wasting taxpayers’ money — and possibly jeopardizing their safety. Research shows that one type of scanner, which uses X-rays, could slightly increase the number of cancer cases [3]. The other scanner, using millimeter waves, has been hampered by false alarms [4] caused by folds in clothing and even sweat.

The TSA says the body scanners are the best technology available and an improvement by leaps and bounds over the metal detectors, which cannot detect explosives or other nonmetallic weapons.

The agency says its body scanners have found more than 300 dangerous or illicit items — everything from a loaded .380-caliber Ruger handgun [5] to exotic snakes [6] that a man tried to smuggle inside his pants.

Last month, TSA administrator John Pistole boasted to Congress that a scanner had picked up a piece of Nicorette gum [7]. And in Buffalo recently, a passenger who was caught with a ceramic knife [8] after a pat-down admitted that he had opted out of the scanner because he figured it would find the knife.

Although the TSA’s machines have yet to find an explosive, screeners frequently come across bottles of alcohol and drugs, which could easily have been a powder or liquid explosive, spokesman Greg Soule said.

Two homeland security officials, who asked not be identified speaking about vulnerabilities, said recent intelligence that terrorists are considering implanting explosives [9] inside their bodies shows that the scanners are forcing would-be suicide bombers to adapt their methods. The body scanners see only underneath clothing, not inside the body. Carrying out an attack with an implanted weapon, the officials said, would be technically more difficult than if an attacker had a bomb strapped to their chest.

The GAO reported [10] in 2010, however, that it was “unclear” if the scanners would have caught the explosive PETN that underwear bomber Umar Farouk Abdulmutallab tried to detonate on a Northwest Airlines flight over Detroit.

After the failed attempt, the TSA ramped up its deployment of two types of body scanners [11] — one using backscatter X-rays and another using low-powered electromagnetic waves, known as millimeter waves. The TSA says both are highly effective, but a small number of studies that have been released publicly raise questions about each machine’s ability to detect explosives.

Last year, Leon Kaufman and Joe Carlson, two physicists at the University of California, San Francisco, simulated what the backscatter X-ray scanners might see if a passenger carefully molded explosives to blend in with the human body. The machines were effective for seeing metal objects hidden on the human body and could detect the hard edges of organic materials, such as a brick of explosives, according to the study published last year in the Journal of Transportation Security [12].

But a thin, irregularly-shaped pancake taped to the abdomen would be invisible in images because it would be easily confused with normal anatomy, Kaufman and Carlson wrote. “Thus, a third of a kilo of PETN, easily picked up in a competent pat-down, would be missed by backscatter ‘high technology,’” they concluded.

“The amount of contrast between an explosive and tissue is very, very low and not in the range where someone viewing the images could discriminate it by eye,” Carlson said in an interview.

Peter Kant of Rapiscan Systems, which makes the backscatter machine, declined to comment on the researchers’ study but said the scanner “has exceeded all aviation security detection testing globally.”

No recent study of the millimeter-wave machine, manufactured by L-3 Communications, could be found. But initial tests at Seattle-Tacoma International Airport in 1996 showed a detection rate of 73 percent.

Bulk plastic explosives were the hardest threat to detect, according to the study by researchers at the Pacific Northwest National Laboratory. Screeners who were new to the machine found nearly all the Glock pistols in the images, but they were able to identify the bulk explosives only 56 percent of the time.

Another study a few years later tested a primitive version of the privacy software now used in airports in which detection is performed by a computer, not a person. The detection rate was comparable, the researchers concluded, but the test did not break down the results by type of threat.

“Certain objects are tougher to find than others,” said Tom Ripp, president of L-3′s security and detection division. “I would think that both technologies have the capability to find these threats. Is it easy to find these threats? I would not say it’s easy to find these threats. But they can be detected.”

Prompted by an outcry over the graphic images the body scanners produce, the TSA began installing privacy software [13] on all of its millimeter-wave machines this summer. Instead of creating an image of the passenger’s body, the machines now display a generic outline of a human body with potential threats highlighted by yellow boxes.

“The TSA has said that automated detection had to be as good as or better than the required detection by an operator,” said Bill Frain, a senior vice president at L-3. “Right now, we’re on par.”

The X-ray body scanner, however, still produces images of passengers’ bodies, which are examined by TSA screeners in a separate room. Rapiscan has developed an automated system, but it is undergoing tests in TSA research labs.

Before such software was developed, many security and imaging experts believed the backscatter X-ray machine produced sharper images than the millimeter-wave machine. Millimeter waves have longer wavelengths than X-rays, resulting in a lower resolution.

But with automated detection software, the machines would no longer produce images, and the ability of the machines to detect threats is more dependent on the algorithms used in the software.

The TSA has spent more than $100 million on the body scanners and plans to spend hundreds of millions of dollars more as it outfits nearly every airport security lane with a scanner by 2014.

Hobby Airport in Houston. Photo by Gail Delaughter/KUHF

(Houston, TX — Gail Delaughter, KUHF)   The Houston Airport System is expecting over two million travelers this holiday season and that means long lines at security at its two major facilities.

Most passengers travel in and out of five terminals at Bush Intercontinental, the sprawling hub 20 miles north of downtown that’s known locally as the “Big Airport.” Budget-minded and short-hop travelers go to Hobby Airport, a much smaller facility that sits at the edge of a residential area in southeast Houston. Hobby handles a much smaller percentage of the traffic, but officials there expect about a three percent increase in travel over last year’s holiday period.

So as families hit the airport laden with luggage and gifts, airport spokeswoman Roxanne Butler is putting out seasonal reminders for folks who don’t travel a lot, stuff that’s become a fact of life for the seasoned business traveler. If you don’t want to bog down the security line, keep it simple.

“Don’t wear all the jewelry, and if you have a belt, make sure it’s easy to get on and off, shoes, easy to slip on and off.”

But there’s good news for parents traveling with cranky kids.

“They are allowing kids 12 and under to keep their shoes on while they’re going through the checkpoints, which will speed it up because we see a lot of large families.”

The three-ounce rule is still in effect for liquids in carry-ons but there are exceptions for medications, baby formula, and breast milk. Butler says aside from what in a bottle, it’s important to consider other items that contain liquids, like a snow globe you may be giving as a gift.

“You know, it’s happened to my family, where they have a jar of olives and they forget, oh my gosh, there is liquid in it. And you have to drain it before you go through the checkpoint.”

Travelers are also being advised again this year to keep gifts unwrapped in case TSA agents need to see inside.

Butler says passengers can stay on top of any delays by following Bush Intercontinental on Twitter @iah and Hobby @HobbyAirport.

The U.S. highway system, mapped as a transit route (image courtesy of Cameron Booth)

The Federal Aviation Administration will release new rules for addressing pilot fatigue today. (The Hill)

House Republicans are calling for a GAO audit into California’s high-speed rail program. (McClatchy via Miami Herald)

Congress moves toward a tougher stance on pipeline safety, but is it enough? (ProPublica)

Now that Troy has rejected federal funds for a regional transit center, other Michigan cities are scrambling to claim it. (Detroit Free Press)

Battered by criticism and low sales, Honda will redesign its Civic — just eight months after releasing the last version. (Changing Gears)

Reimagining highway routes as a transit map. (Cambooth.net)

The nostalgia train brought out New Yorkers’ inner flappers/Southern gentlemen/vaudeville hosts. (Wall Street Journal)

Cap’nTransit asks: will Cornell’s Applied Sciences campus on New York’s Roosevelt Island be car-free?

TSA agents in Los Angeles are trying to get on passengers’ good sides by singing holiday carols. (Marketplace; video below)

The scanner, known as the millimeter-wave machine, uses low-level electromagnetic waves that, unlike X-rays, have not been linked to cancer. The Transportation Security Administration already uses the millimeter-wave machine and says both types of scanners are highly effective at detecting explosives hidden under clothing.

But two of Europe’s largest countries, France and Germany, have decided to forgo the millimeter-wave scanners because of false alarms triggered by folds in clothing, buttons and even sweat.

In Germany, the false positive rate was 54 percent, meaning that every other person who went through the scanner had to undergo at least a limited pat-down that found nothing. Jan Korte, a German parliament member who focuses on homeland security, called the millimeter-wave scanner “a defective product.”

While it’s difficult to know for sure if the millimeter-wave machine has a worse false-alarm rate than the X-ray machine, recent tests suggests that it does. The TSA wouldn’t release its results, citing national security. But a British study found the X-ray machine had a false-alarm rate of just 5 percent.

For the millimeter-wave machines, a complicating factor is new privacy software [2] that was installed in many countries after a public outcry over the scanners’ graphic images. The software automates detection and no longer creates an image of a passenger’s body. While false alarms were reported before automation when human screeners interpreted images, the software appears to have made the problem worse.

The privacy safeguards are also an obstacle to lowering the false-alarm rate, researchers say. The machines do not save images or data, which could be used to teach the software how to distinguish real threats from false ones.

The problem of false alarms comes down to fundamental physics. Millimeter waves penetrate clothing and reflect off objects. But because of their frequency, millimeter waves also reflect off water, which can cause the scanner to mistake sweat for a potentially dangerous object, said Doug McMakin [3], the lead researcher who developed the millimeter-wave scanner at the Pacific Northwest National Laboratory. (X-rays, which operate at a higher frequency, pass through water more easily.)

In addition, millimeter waves penetrate clothing materials differently, and layers of clothing can create a barrier, triggering a false alarm.

“These are known as clutter issues in the imaging,” McMakin said.

The manufacturer, L-3 Communications, said that in the United States the scanners have not experienced a high rate of false alarms caused by either clothing or sweat. L-3 executives noted that the millimeter-wave machine is installed in airports in some of America’s most humid cities, including Houston, New Orleans and Miami.

But as late as last November, the head of the TSA told Congress that false alarms were too frequent to deploy the privacy software. The TSA said the rate has improved since then and now meets its standards, which it would not disclose.

“As with many types of technology, there will be an anticipated amount of false alarms that are considered acceptable, and we continue to work with industry vendors to improve both the detection and operational capabilities for all of our technology,” spokesman Greg Soule said.

But results from other countries, as well as tests conducted in the United States before 9/11, show false alarms occurred between about a quarter and half of the time. Moreover, dozens of U.S. travelers told ProPublica they had to get a pat-down despite passing through the body scanners.

Only one report of the false alarm rate for the X-ray body scanners could be found. At Manchester Airport in the United Kingdom, where 13 machines have been tested on more than 2.5 million people, the rate has been less than 5 percent — and that includes passengers who left items such as keys in their pockets, said airport spokesman John Greenway.

Referring to the false alarm rate, Peter Kant of the manufacturer, Rapiscan Systems, said, “Our numbers internally are in the very low single digits.” The company, as well as several physicists, said sweat does not cause false alarms with the X-ray scanners.

In an effort to close a gaping hole in its ability to catch explosives, the TSA in 2009 began installing body scanners alongside metal detectors for routine screening. The deployment ramped up quickly after a Nigerian man tried to blow up a plane that Christmas with explosives hidden in his underwear.

The TSA purchased both types of scanners [4] with plans to deploy them at nearly every security lane by 2014. In hubs, such as Atlanta and Dallas-Fort Worth, it installed millimeter-wave machines, which look like round glass booths and emit low-powered electromagnetic waves similar to those found in police radar guns.

In other major airports, such as Los Angeles and Chicago O’Hare, it installed X-ray machines, also known as backscatters, which look like two large blue boxes and emit extremely low levels of ionizing radiation, a form of energy that strips electrons from atoms and damages DNA, potentially leading to cancer.

The possible health risk of the X-ray scanners, while small, has prompted several prominent radiation experts to ask why the TSA doesn’t just use the millimeter-wave machine. The agency has said keeping both technologies in play encourages the contractors to improve their detection capabilities and lowers the cost for taxpayers.

The United States is almost alone in deploying the X-ray body scanners for airport security: Nigeria has installed them, and the United Kingdom is testing them for random screening and to check passengers who have set off the metal detector. Last month, the European Union prohibited the X-ray machines [5], effectively leaving the millimeter-wave scanner as the only option in Europe.

The United Kingdom will have to stop using the machines once its test is completed, according to the European Commission. But the commission has also asked one of its scientific committees for a health study that could change its position on the backscatters.

Guns, Sweat and Privacy Fears

During a Republican presidential debate in 1988 [6], George H.W. Bush, pulled out a .22-caliber miniature revolver made with only a small amount of metal to dramatize the new types of guns that could pass through airport metal detectors.

“That weapon at this point cannot be detected,” he said. “That weapon can kill the pilot of an airplane.”

The comments, along with concerns over a new Glock pistol made of plastic, spurred the Federal Aviation Administration, which was then in charge of security, to fund research into a millimeter-wave imaging system at the Pacific Northwest National Laboratory.

After 9/11, the lab licensed the technology to a startup company, which was acquired by L-3 in 2006.

When the scanners debuted, TSA officials boasted that they were so good at detection, that screeners could literally see the sweat on someone’s back.

At that time, human operators viewed the image. Although sweat might appear similar to a threat, trained officers learned to recognize normal sweat patterns, said Kip Hawley, TSA administrator from 2005 to 2009. In fact, sweat could help officers detect a sheet explosive, he said, because something taped or glued to the body changes the natural sweat pattern.

“It never popped up where we said, ‘Oh God, we’re getting killed with false positives,’” Hawley said. “I think it’s a training issue, training the officers on interpreting the images.”

But because of the uproar over agents seeing passengers’ bodies — what critics decried as a “virtual strip search” — other countries began installing automated detection software last year, and the TSA followed suit in July.

Now, instead of displaying an image of a particular passenger’s body, the machine shows a generic, unisex outline that’s reminiscent of the cartoon character Gumby. Any potential threat is indicated by a yellow box that shows up roughly where the software detected it — on the right ankle, for example, or the left elbow.

“It looks for abnormalities,” said Tom Ripp, president of L-3′s security and detection division. “It looks for objects that are not supposed to be there.”

The advantage, L-3 officials said, is that screeners can focus their checks on the highlighted area instead of patting down a passenger’s entire body.

“If you go out to an airport like D.C., Reagan, you’ll see how easily the process works,” said senior vice president Bill Frain. “Usually somebody left something in their pocket. We sat there and watched for 20 minutes. The duration between an alarm and a check — they were just putting people through. It was a very quick check.”

The European Experience

That wasn’t the case in Germany.

The German interior ministry tested two L-3 body scanners with the automated detection software at Hamburg Airport, screening 809,000 airline passengers from September 2010 through July 2011. Despite the high rate of detection, the delays caused by frequent false alarms were so unbearable that Germany decided that the technology was not ready for everyday use.

Nearly seven out of 10 passengers had to be stopped for further screening. Although some passengers had forgotten coins or tissues in their pockets, 54 percent of all passengers who went through the scanners triggered true false alarms — meaning that no hidden objects were found on those people, a ministry spokesperson said.

The vast majority of false alarms, affecting 39 percent of all passengers, were attributed to sweat, buttons or folds in clothing. Another 10 percent resulted from passengers moving during the scan, while 5 percent couldn’t be explained at all.

Ripp from L-3 said the high alarm rate comes down to how diligent the screeners are about asking passengers to take off belts and boots, remove bulky sweaters and assume the proper stance with their hands over their heads. In the United States, the stance has become routine, he said.

“That was not the case in these trials in Hamburg,” Ripp said.

The German interior ministry, however, dismissed the idea that it hadn’t followed the manufacturer’s protocol. Officials there provided ProPublica with a flier [7] that was handed out to passengers before the screening that specifically tells them how to stand and to remove sweaters, belts and boots.

“Prior to the field test, the security personnel was specially trained to deal with body scanners and has adhered to the control procedure,” the spokesperson said via email. “The passengers were asked to take off the named items.”

Germany wasn’t the only country to have problems with false alarms.

France tested the scanners with and without the privacy software on more than 8,000 passengers flying out of Paris’s Charles de Gaulle Airport to New York from February to May 2010. But the government decided not to deploy them because there were too many false alarms, said Eric Heraud, a spokesman for the French civil aviation authority.

Heraud wouldn’t release specific figures but said the false alarm rate was higher with the automated detection than when officers interpreted the images. France plans to conduct a new test of the millimeter-wave scanners in 2012.

In Italy, the rate of false alarms was 23 percent, said Giuseppe Daniele Carrabba, head of the airports coordination department for the Italian civil aviation authority.

Italy tested two L-3 scanners with the automated detection software at the airports in Rome and Milan. The test ended in September, and officials are awaiting a final decision on whether to deploy the machines later this month. Carrabba said he thinks Italy will use them, and that the false positive rate will improve with more training and better preparation of the passengers for screening.

L-3 attributed the variations in experiences to the different settings that countries choose for what to detect and what to ignore.

Other countries that have deployed millimeter-wave scanners — Canada with 51 machines and the Netherlands with 60 — said they had not experienced problems with false alarms. They declined to disclose their false-positive rates.

The American Experience

In the United States, the TSA has deployed more than 250 millimeter-wave machines and plans to install 300 more by next spring.

The TSA declined to answer detailed questions. Instead, the agency released a statement saying that it had tested the automated detection software rigorously.

“Once it met the same high standards as the technology currently in use, TSA successfully tested the software in airports to determine whether it was a viable option for deployment,” the statement said. “While there are no silver bullet technologies, advanced imaging technology with this new software is effective at detecting both metallic and non-metallic threats.”

Shortly after the machines were developed, preliminary tests at Seattle-Tacoma International Airport in 1996 resulted in a false alarm rate of 31 percent, according to a research paper presented at a conference the following year. During the tests, screeners who were new to the machine viewed images of people carrying various weapons, explosives and innocuous objects and had up to 27 seconds to identify them. According to the paper, researchers did test the results with layered clothing.

In 2000, those same images were run through a primitive model of the automated detection and privacy software. The false alarm rate increased to 38.5 percent when the machine was set on high sensitivity but decreased to 17 percent when set on low sensitivity, according to another study by the same researchers at the Pacific Northwest National Laboratory.

“Overall, these results show comparable performance” between the software and the human screeners, the researchers concluded.

The TSA ran additional tests over several years before deploying the scanners, but late last year, administrator John Pistole told Congress the tests were still showing a high rate of false alarms with the software. Officials said the false alarm rate improved, and the agency began installing the software over the summer.

Still, American travelers frequently complain about false positives similar to those experienced in Europe.

Lynne Goldstein, an archaeologist at Michigan State University, said she generally prefers the scanners because, with two knee replacements, she always sets off the metal detectors and has to undergo a pat-down.

But, she said, a cotton shirt she frequently wears while traveling set off the millimeter-wave machine several times while flying out of Detroit. TSA agents told her it was the shirt’s “kangaroo pocket” similar to those found on sweatshirts that triggered the alarm.

“The last time, they did a full pat-down,” Goldstein said. “The thing that’s ironic to me: I actually like the machine.”

Many travelers, however, also reported false alarms with the X-ray body scanner.

Jason Ritchie, an associate chemistry professor at the University of Mississippi, said he was flying out of Memphis on his way to a conference in August when the operator of the X-ray machine spotted something that required further checking.

The suspicious item: The pockets of his cargo pants, he was told.

“It kind of annoys me when I have to go through the X-ray system because I don’t like to be irradiated unnecessarily,” Ritchie said. “To have to go through that and then be told I also had to get a pat-down was frustrating.”

ProPublica tried to get a handle on the false alarm rate in the United States by commissioning a poll by Harris Interactive. The poll of 2,198 people was conducted online to ensure that those who responded could view images of the machines in addition to reading a description.

Of the 581 people who said they had taken a flight in the past six months, nearly two-thirds, or 367, reported going through a body scanner.

About 11 percent of those scanned said they were patted down anyway despite having nothing on them — the equivalent of a false alarm.

Among this group, the rate of false alarms was slightly higher for the millimeter-wave machine over the X-ray scanner. But Harris Interactive cautioned that because the sample size of people reporting this experience was small, the result cannot be generalized to the population at large.

Possible Solutions

Improving the technology to increase detection but limit false alarms is extremely challenging because of the great variety of body shapes and clothing, said McMakin of the Pacific Northwest National Laboratory.

The machine can be taught to recognize patterns in clothing such as a left breast pocket in men’s dress shirts, he said. But whereas screeners could generally see the outline of an abnormal pocket or buttons in an image, the privacy software eliminates such human discretion.

One option is to combine the millimeter-wave scan with an optical camera to weed out those issues, McMakin said. For example, software could compare the millimeter-wave scan with the photograph to determine if a button or a zipper was causing the alarm. Developers could also increase or decrease the frequency of the waves or improve the shape and location information in the algorithm, he added.

“We’re just at the beginning of where this technology can go,” McMakin said.

Ripp from L-3 said it all comes down to “machine learning.”

Getting the information of what’s normal in order to improve the technology requires many thousands of scans. But because of the privacy outcry, the machines used in airports do not save the images or data from the scans. Without that real-world data, developers have to find other ways to teach the software to distinguish real threats from false ones.

Christian Salewski, a former fellow at ProPublica and a staff writer for the Financial Times Deutschland, reported from Hamburg.

Ontario International Airport, California. (photo by richmanwisco via flickr)

(by Michael Grabell, ProPublica) Even if X-ray body scanners would prevent terrorists from smuggling explosives onto planes, nearly half of Americans still oppose using them because they could cause a few people to eventually develop cancer, according to a new Harris Interactive poll conducted online for ProPublica.

Slightly more than third of Americans supported using the scanners, while almost a fifth were unsure.

The Transportation Security Administration plans to install body scanners, which can detect explosives and other objects hidden under clothing, at nearly every airport security lane in the country by the end of 2014. It’s the biggest change to airport security since metal detectors were introduced more than 35 years ago.

The scanners have long faced vocal opposition. Privacy advocates have decried them as a “virtual strip search” because the raw images show genitalia, breasts and buttocks – a concern the TSA addressed by requiring software that makes the images less graphic. But in addition to privacy objections, scientists and some lawmakers oppose one type of scanner because it uses X-rays, which damage DNA and could potentially lead to a few additional cancer cases among the 100 million travelers who fly every year. They say an alternative technology, which uses radio frequency waves, is safer.

Some travelers like Kathy Blomker, a breast cancer survivor from Madison, Wis., have decided to forgo the machines altogether and opt for a physical pat-down instead. “I’ve had so much radiation that I don’t want to subject myself to radiation that I can avoid,” she said. “I decided I’m just not ever going to go through one of those machines again. It’s just too risky.”

After ProPublica published an investigation, reported in conjunction with PBS NewsHour, showing that the X-ray scanners had evaded rigorous safety evaluations, the head of the TSA told Senator Susan Collins that his agency would conduct a new independent safety study. He subsequently backed off that promise, prompting the senator to write the TSA pressing the agency to go ahead with the study and asking it to post larger signs alerting pregnant women that they have the option to have a physical pat-down instead of going through the X-ray scanners.

The TSA has repeatedly touted a series of polls showing strong public support for the scanners. But those polls and surveys – conducted by Gallup, The Wall Street Journal and various travel sites – largely dealt with the privacy issue.

Only one of those polls – by CBS News – asked specifically about X-ray body scanners, finding that 81 percent of Americans thought that such X-ray scanners should be used in airports. But that poll – like all the others – did not mention the risk of cancer.

When confronted with the cancer-terrorism trade-off, however, Americans took a much more negative view of the scanners.

Harris Interactive surveyed 2,198 Americans between Dec. 2 and Dec. 6. (Full survey methodology can be found here.) The international polling firm asked, “If a security scanner existed which would significantly help in preventing terrorists from boarding a plane with powder, plastic, or liquid explosives, do you think the TSA should still use it even if it could cause perhaps six of the 100 million passengers who fly each year to eventually develop cancer”

Forty-six percent said the TSA shouldn’t use it, 36 percent said it should, and 18 percent weren’t sure.

Asked to comment, TSA spokesman Michael McCarthy said in a statement that the X-Ray scanners are “well within national standards.”

“TSA’s top priority is the safety of the traveling public and the use of advanced imaging technology is critical to the detection of both metallic and non-metallic threats,” he said. “All results from independent evaluations confirm that these machines are safe for all passengers.”

The number of potential cancer cases used in the poll comes from a peer-reviewed research paper written by a radiology and epidemiology professor at the University of California, San Francisco, and posted on the TSA’s website.

The professor, Rebecca Smith-Bindman, concluded that ‘there is no significant threat of radiation from the scans.’ But she estimated that among the 750 million security checks of 100 million airline passengers per year, six cancers could result from the X-ray scans. She cautioned that the increase was small considering that the same 100 million people would develop 40 million cancers over the course of their lifetimes.

Another study by David Brenner, director of Columbia University’s Center for Radiological Research, estimated that as airlines approach a billion boardings per year in the United States, 100 additional cancers per year could result from the scanners.

The TSA uses two types of body scanners to screen travelers for nonmetallic explosives. In the X-ray machine, known as a backscatter, a passenger stands between two large blue boxes and is scanned with an extremely low level of ionizing radiation, a form of energy which strips electrons from atoms and can damage DNA, leading to cancer. In the millimeter-wave machine, a passenger stands inside a round glass booth and is scanned with low-energy electromagnetic waves which don’t strip electrons from atoms and have not been linked to cancer.

There is a great deal of uncertainty when performing cancer risk assessments from the very low levels of radiation that the backscatters emit. The U.S. Food and Drug Administration put the risk of a fatal cancer from the machines at one in 400 million. The U.K. Health Protection Agency has put it at one in 166 million.

Some experts say such estimates of population risk create a distorted picture of the danger because humans are constantly exposed to background radiation and already accept risks that increase exposure, such as flying on a plane at cruising altitude.

In the authoritative study on the health risks of low levels of radiation, the National Academy of Sciences concluded that the risk of cancer increases with radiation exposure and that there is no level of radiation at which the risk is zero.

Given that risk, Brenner and some in Congress have argued that the TSA should forgo in the X-ray scanners in favor of the millimeter-wave machine.

European officials have gone so far as to prohibit the X-ray body scanners, leaving the millimeter-wave scanner as the only option. But some countries, including Germany, have reported a high rate of false alarms with the millimeter-wave machines.

The TSA has said that keeping two technologies in play creates competition, encouraging the manufacturers of both technologies to improve the detection capabilities, efficiency and cost of the scanners.