As privacy and digital rights advocates continue to question the accuracy and ethics of using facial recognition systems, and technology executives ask Congress to step up and provide some regulation of them, a group of senators is asking the heads of nearly 40 law enforcement agencies to provide details of whether, how, and why they use the technology and who they’re buying it from.

In a letter sent July 27, Sens. Ron Wyden (D-Ore.), Cory Booker (D-N.J.), and Ed Markey (D-Mass.), expressed concerns about the accuracy of facial recognition systems, as well as their effects on individuals’ privacy. The lawmakers asked 10 specific questions of the chiefs of 39 federal law enforcement agencies, a diverse group that includes the FBI, Drug Enforcement Administration, Amtrak Police, United States Mint Police, and the U.S. Fish and Wildlife Service Office of Law Enforcement.

The letter asks the agencies to provide general information such as whether they use facial recognition systems, the circumstances in which they use the systems and what the goals are, as well as some much more specific questions. For example, the letter asks each agency to name any specific databases they run facial matches against, and whether the agency conducts audits to check the accuracy of their systems.

“As these technologies have increased in availability and accuracy, and decreased in cost, we understand that as a law enforcement tool this technology would appear attractive,” the senators wrote. “However, this technology comes with inherent risks, including the compromising of Americans’ right to privacy, as well as racial and gender bias. As such, in exercising its oversight role, it is important for Congress to better understand the degree to which federal law enforcement agencies may be employing these new technologies.”

"This technology comes with inherent risks, including the compromising of Americans’ right to privacy."

Facial recognition systems have come under increased scrutiny recently from lawmakers, digital rights groups, and even some of the companies selling the technology. The American Civil Liberties Union recently conducted a test of Amazon’s Rekognition technology, comparing photos of all of the members of Congress to a database of people who have been arrested. The system mis-identified 28 members of Congress in that test, which came soon after Microsoft President Brad Smith appealed publicly for Washington to put together federal regulation of the use of facial recognition technology.

“Without a thoughtful approach, public authorities may rely on flawed or biased technological approaches to decide who to track, investigate or even arrest for a crime,” Smith said.

Although, experts say the chances of Congress moving on regulation in the near future are low, the letter from Wyden, Booker, and Markey, indicates that some legislators are thinking about the ways in which the technology is used and what the potential privacy and security issues might be. One of the major concerns about these systems is their accuracy, especially in correctly identifying people of color, particularly women. In their letter, the senators ask the agencies to specify whether any audits they conduct "assess whether search results are biased on the basis of race, gender, ethnicity, or age."