When Wisconsin-based tech company Three Square Market offered to pay for its employees to be voluntarily microchipped last summer, the Internet was aghast. But just days before the so-called “chip party” at the 3SM company headquarters, people at the DEFCON hacking conference were eagerly lining up and paying to get microchip implants injected into the subdermal fascia between their thumbs and forefingers.

This juxtaposition begs the question: are these chip implants a step toward an invasive dystopian future where employers track their subjects’ every movement? Or are they simply an easy way to log in to accounts and open doors with the flick of a wrist? With a small but growing number of chipped individuals (between 50,000 and 100,000 according to estimates from biohacking company Dangerous Things) taking the plunge, society may soon find out.

What we’re talking about when we talk about microchips

Microchip implants are generally shaped like cylinders. They contain a small microchip, a bio-safe epoxy resin, and a copper antenna wire coil encased in lead-free borosilicate glass or soda-lime Schott 8625 biocompatible glass. Microchips used for both animals and humans are field powered and have no battery or power source. Therefore, they are inert until they come within the field produced by a reader device, which implants communicate with over a magnetic field.

These implants often fall under the RFID (radio-frequency identification) umbrella, and RFID technology encompasses a very broad spectrum of frequencies, devices, protocols, and interfaces. RFIDs are typically found in three frequency families: low-frequency (125 and 134 kilohertz), high-frequency (13.56 megahertz), and UHF (800-915 megahertz). Chips sold for implants are generally either low or high frequency. RFID chips are identified using radio waves, and near-field communication (NFC) chips are a branch of high-frequency radio waves.

Biohax, the company that installed chips for the 3SM employees who wanted them, sells near-field communication devices, while other companies like Dangerous Things let users select between RFID and NFC chips, for example. People typically use RFID tech to replace keys and passwords, so they can enter their home, unlock and start their car, or log in to a laptop more conveniently. NFC tags can be used to store vCards or Bitcoin wallet addresses, among other things. In Sweden, Biohax partnered with the railways, and chips can be used as ticket carriers. It’s also possible to program chips as different types of triggers so you can, for example, tap your phone to your chip and contact your spouse.

Dangerous Things’ 125 kHz xEM chips emulate common low-frequency EM41xx style chips, have some programmable memory space and basic security features, and allow you to program or clone EM or HID tag IDs, such as ProxMark II card IDs. Their 13.56MHz xNT chips are higher frequency and are based on the NTAG216 chip. They have 888 bytes of user programmable memory and 32-bit password protection security features. They are NFC compliant. The company’s 13.56 MHz xMI microchips have 769 bytes of user programmable memory and support Crypto1 security features, but those are only supported on some NFC devices. The company’s 3.56 MHz xIC devices have 128 bytes of programmable memory but no security features, and these are only supported on some NFC devices.

Dangerous Things often refers to microchip implants as transponders, a portmanteau for transmitter-responder. But information security researcher Tarah Wheeler, a Principal Security Advisor at Red Queen Technologies and Cybersecurity Fellow at New America, believes the term is inaccurate when used to refer to unpowered magnetic memory such as USB drives or implantable microchips. Again, these chips are unpowered, have teeny tiny antennas, and don’t really transmit anything. “You’re lucky if it’s anything beyond a foot at maximum. In reality, functionally, you must touch it to the device to get a read,” she says.

The health risks

These days, microchips are so safe that they’re used by pet owners to tag their own dogs and cats. In fact, the risk to humans from an ear-piercing is greater since chip implants scab over far more quickly—in a matter of hours. Still, Dangerous Things CEO Amal Graafstra warns that if people try to insert the chips themselves and don’t follow aseptic procedure, they may get an infection. And infections can sometimes (rarely) lead to MRSA, a type of staph infection that has become resistant to many antibiotics and can sometimes be deadly. The risk of infection is reduced by working with a professional body piercer skilled with needles and aseptic procedures, which is why Dangerous Things has a network of partners to recommend (including some who can install more involved products). The biohacking supply company’s X-series devices are usually sold pre-loaded inside a sterile injection assembly.

Upon installation, the tags do cause a moderate amount of swelling for up to around a day and some bruising for a few days. It can take two to four weeks for the tag to get encapsulated with fibrous collagen tissue, and users might have some temporary itching or pinching sensations for up to two years as the body heals around the tag.

But after a tag has healed, it can’t be felt under the skin, and it usually can’t be seen under most people’s hands unless they’re gripping large objects, according to Dangerous Things. It’s possible for the skin covering the tag to get pinched between the tag and another object, which can be mildly painful, but this can be prevented by not rolling the tag between hard surfaces.

The most inexpensive microchips sold by Dangerous Things are encapsulated in biosafe glass and are inserted in the skin between the thumb and index finger. Though they are not indestructible, they are far less likely to break when inside the human body.

Implantable microchips are compatible with MRI machines and are not picked up by metal detectors or airport scanners. And if a person ultimately second-guesses the thing, they’re also not difficult to take out. Animal chips are coated with biobond or parylene, but human chips are not, which makes removal easier. A doctor can put a glove on, make a small incision, and press the chip up from the skin to get it right out. (In 2004, Verichip offered an implantable microchip meant to unlock personal health records. It was injected into the triceps muscle and was coated in bio-bond and was meant to be permanent, so the device could only be removed with much pain and scar tissue. The process has evolved, however, so this doesn’t apply to the implantable chips being used today.)

One health concern Graafstra sometimes hears comes from people who are convinced that they have had a chip implanted against their will. These individuals say that such a chip is somehow making them hear voices or see flashes of light or experience other phenomena. This fear is sometimes due to undiagnosed mental illness, and sometimes it’s because of scammers that claim to scan people for chips and offer removal services. “If there was a neural interface that was that good, it would be the holy grail of computer/brain interfaces,” Graafstra says. In reality, even the most advanced neural interface implants do little more than talk to a few neurons. The CEO has investigated some of these claims and reported his findings. Now when someone approaches him to ask about chip-inspired voices or visions, he recommends that they see a doctor, preferably one specializing in neurological disorders.