In the week since EFF and the Associated Press exposed how Fog Data Science purchases geolocation data on hundreds of millions of digital devices in the United States, and maps them for easy-to-use and cheap mass surveillance by police, elected officials have voiced serious concerns about this dangerous tech.

In a strong letter to Lina Khan, the chair of the Federal Trade Commission (FTC), Rep. Anna Eshoo of California on Tuesday criticized the “significant Fourth Amendment search and seizure concerns” raised by Fog and urged the FTC to investigate fully. As public records obtained by EFF show, police often use Fog’s mass surveillance tools without a warrant, in violation of our Fourth Amendment rights.

Eshoo wrote:

“The use of Fog is also seemingly incompatible with protections against unlawful search and seizure guaranteed by the Fourth Amendment. Consumers do not realize that they are potentially nullifying their Fourth Amendment rights when they download and use free apps on their phones. It would be hard to imagine consumers consenting to this if actually given the option, yet this is functionally what occurs.”

Eshoo also pointed out the new threat that Fog’s surveillance tool poses to people seeking reproductive healthcare. In a state where abortion has been criminalized, Fog’s Reveal tool could potentially allow police, without a warrant, to draw a geofence around a health clinic over state lines in a state where abortion is not criminalized, allowing them to see if any phones there return to their state. “In a post Roe v. Wade world., it’s more important than ever to be highly mindful of how tools like Fog Reveal may present new threats as states across the country pass increasingly draconian bills restricting people’s access to abortion services and targeting people seeking reproductive healthcare,” Eshoo wrote.

The FTC recently sued another company selling geolocation data, Kochava, a commendable step to hold the company accountable for its unfair practices.

Eshoo is not alone. Senator Ron Wyden said in a tweet about Fog’s ability to facilitate mass surveillance, “Unfortunately, while it’s outrageous that data brokers are selling location data to law-enforcement agencies, it’s not surprising.”

We echo Eshoo’s request that the FTC conduct a full and thorough investigation into Fog Data Science. We continue to urge Congress to act quickly to regulate this out-of-control industry that jeopardizes our privacy, and allows police to conduct warrantless mass surveillance.