Sen. Chris Coons, a Democrat from Delaware and member of the judiciary committee, sent a letter Thursday to the Amazon CEO about the company's privacy and data security practices, saying the could be putting users' privacy at risk.
Coons' letter follows a CNET report from earlier this month that.
"Recent reporting suggests that Amazon's customers may not have as much control over their privacy as Amazon had indicated," Coons wrote.
"While I am encouraged that Amazon allows users to delete audio recordings linked to their accounts, I am very concerned by reports that suggest that text transcriptions of these audio records are preserved indefinitely on Amazon's servers, and users are not given the option to delete these text transcripts."
The inability to delete the text transcript of the audio recordings "renders the option to delete the recording largely inconsequential," the senator said.
Coons has asked for Amazon to provide answers on how long it stores the transcripts, whether users can delete them, why Amazon collects or uses them, and whether Amazon takes any measures to anonymize customer identity.
He also wants to know whether Amazon preserves Alexa's responses in either audio or text, and whether this is deletable, and he wants details on Amazon's Wake Word system, including how long the system records for, whether any audio is sent to the cloud if the wake word isn't detected, whether audio stored in the Echo's temporary memory is transcribed and sent to the cloud, and whether a non-wake word capability is default or must be enabled by a user.
Coons wants a response from Amazon by June 30, 2019.
Once Alexa hears its wake word, which could be "Echo," "Alexa" or "computer," the Echo starts listening and transcribing what it hears. Though Amazon allows you to erase those voice recordings, it keeps the data as a text file on its cloud servers.
Earlier this month, Amazon said it deletes the text files from Alexa's main system, and is working on making them removable from other areas of the system.
"When a customer deletes a voice recording, we also delete the corresponding text transcript associated with their account from our main Alexa systems and many subsystems, and have work underway to delete it from remaining subsystems," an Amazon spokesperson said in an email.
Amazon has sold more than 100 million Alexa devices, dominating the smart speaker market with around 70% market share. It's followed by Google Home, with 24% of the market, and the Apple's HomePod, with 6%.
The tech giant has also come under fire after a group of 19 consumer and public health advocates filed a complaint with the Federal Trade Commission over the Amazon Echo Dot Kids Edition in May.
The complaint alleged that the Dot was retaining children's data even after their parents deleted the voice recordings.