A new lawsuit claims that Amazon’s speaking assistant Alexa is collecting voice data without the consent of customers, which the tech giant allegedly uses to target ads at them.

Filed in a U.S. District Court in Seattle a week ago, the lawsuit is seeking certification as a class action that, if approved, may potentially include millions of smart speaker customers as plaintiffs.

“Amazon’s customers agreed to allow Alexa into their homes for a very specific and limited purpose — responding to and executing voice commands and queries. Nothing in Alexa’s terms of service or privacy policy discloses or obtains authorization for usage of their voice recordings for advertising purposes,” the suit says. 

According to the latest data from the Consumer Intelligence Research Partners, Amazon leads a growing smart speaker market, commanding almost 70 per cent of the market share and more than 80 million of its devices operating in over 50 million homes.

If there is truth to the lawsuit’s claims, millions of American households are vulnerable to ad targeting without their consent, through a device that they purchased and brought into their homes.

Amazon has consistently denied using voice data from Alexa to target ads at customers.

Despite the tech giant’s denials, researchers from the University of Washington and three other universities published a research paper in April that says otherwise.

The researchers created personas to use Echo devices and established a framework to measure Amazon’s collection, usage and sharing of their interaction data. They likewise tracked ads targeted to each persona, and concluded that the retail giant was “processing voice data to infer user interests” in those ads.

The researchers also noted that “Amazon’s inference of advertising interests from users’ voice interactions seems to be inconsistent with their public statements.”

The plaintiffs and potential class representatives to the suit are James Gray from Ohio and Scott Horton from Massachusetts, who both own four Alexa-enabled devices in their homes.

The suit cites four causes of action against the tech giant, including invasion of privacy, infringement of personal rights and violations of fair dealing in contracts and in Washington’s consumer protections law.