Credit: CC0 Public Domain Facebook shared user information with dozens of hardware and software makers, as well as application developers, well after it said it cut off outside companies' access to the data in 2015.
The setups were described in 747 pages of documents submitted to the House Energy and Commerce Committee late Friday in response to hundreds of questions lawmakers had asked company executives.
The disclosures come amid widening scrutiny of how well Facebook protects the personal information of the network's users and their friends.
The social networking giant said it made the special arrangements so hardware and software makers could ensure Facebook worked on their devices and operating systems and application developers had time to comply with the company's stricter access policies.
All told, 52 hardware and software makers—including Apple, Blackberry, Amazon and Microsoft—had access to the data. But the list also includes Chinese firms such as Huawei and Alibaba, some of which generated national security concerns.
Facebook said it has ended 38 of the 52 partnerships. It said it will shut down an additional seven by the end of July and another one by the end of October. Among the handful that will continue beyond that are those with Amazon, Apple and Alibaba.
"We engaged companies to build integrations for a variety of devices, operating systems and other products where we and our partners wanted to offer people a way to receive Facebook or Facebook experiences," the company said in the documents. "These integrations were built by our partners, for our users, but approved by Facebook."
The company said it forged the relationships before the spread of powerful iPhone and Android operating systems that have allowed consumers to easily access the web. Back then, people "went online using a wide variety of text-only phones, feature phones and early smartphones with varying capabilities," Facebook said.
Facebook also gave 61 app developers about six months beyond a May 2015 deadline to comply with more restrictive access to Facebook's computer programming code. Those developers included companies such as AOL, Audi, Panasonic and Hinge, a dating app, which also had information on users' friends, such as phone numbers.
The deals with developers and hardware and software makers were reported by The Wall Street Journal and The New York Times early last month, but the new documents detail the number of companies involved and the extent of the setups.
Facebook has been under fire since it was revealed earlier this year that a political ad targeting firm, Cambridge Analytica, purchased data on up to 87 million users from Facebook without their consent. Facebook CEO Mark Zuckerberg appeared before Congress in April and apologized for not doing enough to protect user data.
The Federal Trade Commission is investigating whether the company's actions violated a 2011 consent decree barring it from making misrepresentations about the privacy or security of consumers' personal information.
Explore further: Facebook says Chinese phone makers got access to data (Update)