From the Left



New Point-and-Shoot Chemical Detectors Raise Privacy and Constitutional Issues

The ACLU on

The TSA has begun testing a new handheld device that purports to be able to quickly identify the substance that someone is carrying just by pointing a laser at it. This kind of device raises serious privacy and constitutional issues.

The device being tested by the TSA is called a "handheld standoff chemical detector," or HSCD. The TSA is testing one from a company called Pendar. Resembling a bulky hairdryer, the operator points it at a powder, liquid, gel or solid and presses a button that shoots a laser at the substance. The device then measures the wavelengths of light that are reflected back, which reveal the chemical makeup of the substance. In a company demonstration video, an operator points the device at a white powder, and the device reports that it is a mix of sugar and ibuprofen, for example. The company says the device can identify any of about 7,500 unique chemicals, usually producing results in seconds from a distance of up to 6 feet, and that it works through glass or other transparent barriers.

Many users of HSCDs are first responders who need to respond to calls about hazardous chemicals, which are regularly dumped illegally due to the expense of disposal, or to the scene of fatal overdoses where responders need to quickly understand what substances they're dealing with. Circumstances like these don't raise compelling privacy issues.

But privacy issues do arise where, for example, police officers are dealing not with detecting imminent threats to safety, but with collecting evidence that can result in possible arrest and prosecution for run-of-the-mill crimes. And if it's being used to tell whether the pills you're carrying in your bag are aspirin, birth control, antibiotics or for the treatment of cancer, high blood pressure or bipolar disorder -- that's a significant invasion of privacy.

According to a press release the TSA issued in July, the agency partnered with the NYPD to test the device during bag searches on people not suspected of any crime in Grand Central Station in New York City. The press release includes a photo of a man standing by while NYPD officers equipped with a Pendar rummage through his backpack.

Normally, the government can't search your bag, purse or other personal effects unless it has a warrant. The courts have carved out an "administrative exception" to that rule at airports and a few other places -- but only for the purpose of protecting security. In 2009, TSA agents started interrogating a man about why he was carrying several thousand dollars of cash and, when he refused to answer questions about his business, called in the police, who detained him. He sued, and as a result the TSA issued directives to its workforce reminding them that their authority is limited to searching for risks to flight safety.


The government should not be able to warrantlessly scan substances carried by a person unless they have a warrant based on probable cause to believe their possession is illegal. So if the TSA or law enforcement is using a device that identifies not just the presence of materials that are dangerous to flights or large crowds, but also the presence of other substances, that raises serious questions under the Constitution.

This device has the potential to greatly expand privacy abuses -- including those stemming from supposedly "voluntary" searches where vulnerable people feel pressured to consent. It's not hard to imagine that HSCDs become smaller, cheaper and more powerful over time, as many electronic devices do. If that happens, their use and abuse may become widespread -- when things get cheap and easy, they tend to be over-used by law enforcement; we've seen this dynamic with cellphone and DNA searches.

The Supreme Court has repeatedly explained that the Fourth Amendment provides powerful protections against police exploitation of modern technologies to invade privacy. When we're arrested, for example, the court has said police may search our pockets to look for weapons and to secure evidence, but they can't look in our phones without a warrant. The high court has also found that the police must get a warrant before using thermal scanning technology to look inside people's homes in a search for marijuana grow operations.

Have DHS and the TSA done a legal analysis of questions such as these prior to deploying the Pendar in a field test in New York City? Do they know how reliable the device is in a real-world setting? To find out answers to these questions, we have filed a Freedom of Information Act request with the agency. New technology is amazing, but it can't be allowed to undercut our constitutional rights.

Jay Stanley (@JayCStanley) is senior policy analyst with the ACLU Speech, Privacy, and Technology Project, where he researches, writes and speaks about technology-related privacy and civil liberties issues and their future. For more than 100 years, the ACLU has worked in courts, legislatures and communities to protect the constitutional rights of all people. With a nationwide network of offices and millions of members and supporters, the ACLU takes on the toughest civil liberties fights in pursuit of liberty and justice for all. To find out more about the ACLU and read features by other Creators Syndicate writers and cartoonists, visit the Creators website at

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