In the wake of the repeal of protections for broadband customers that would have prevented internet service providers from collecting and selling user data without permission, Senate Democrats are asking telecommunications companies to provide more details about their privacy policies.

The group of Senators, led by Ed Markey of Massachusetts, sent a list of questions about privacy practices to major mobile carriers Verizon, AT&T, T-Mobile and Sprint, and internet service providers Charter and CenturyLink.

Read: Congress Decides To Kill Rules Preventing ISPs From Collecting, Selling Data

The questions focus primarily on the company’s policies regarding the use of sensitive user information for the purposes of advertising.

Many of the queries posed by the Senators revolve around some of the requirements that would have been imposed on the ISPs had the Broadband Consumer Privacy Rules, passed by the Federal Communications Commission in October 2016 under President Barack Obama.

The Senators ask if ISPs get opt-in consent from users before using or selling any sensitive information, including web browsing history and app usage data. ISPs have argued that browsing history and app usage is not sensitive information and should not require an opt-in from users before it can be collected and used.

The group also asked about data security practices and how companies choose to report potential data breaches to customers. Under the Broadband Consumer Privacy Rules, ISPs would have been required to alert users within 30 days of identifying a breach. That protection was stayed by FCC chairman Ajit Pai before it was eventually repealed through the use of the Congressional Review Act.

Read: How To Protect Your Browsing History: Internet Service Providers Argue Against Your Privacy

The list of 16 questions, which closes with a request for ISPs to disclose any changes they have made to their privacy policies since the repeal of the Broadband Consumer Privacy Rules, was signed by Senators Al Franken of Minnesota, Richard Blumenthal of Connecticut, Elizabeth Warren of Massachusetts, Bernie Sanders and Patrick Leahy of Vermont, Ron Wyden of Oregon and Chris Van Hollen Maryland.

The senators have requested a response to their questions by May 1.