The Senate Commerce Consumer Protection subcommittee will focus on kids’ privacy in a hearing Thursday on consumer protection in the mobile market.

On Wednesday, Commerce chair Sen. Jay Rockefeller (D-W.V.) sent letters to Apple and Google asking how well their apps and the apps in their mobile application stores comply with the Child Online Privacy Protection Act.

COPPA focuses on protecting children 13 and under, leaving teens — among the most prolific users of mobile technology — in a vulnerable position, The Washington Post reported.

In written testimony released before the hearing, Common Sense Media’s Amy Guggenheim Shenkan said teens should be explicitly protected by clear and transparent privacy laws, and that parents and kids should have the right to delete young users’ personal online information.

The panel will look closely at apps, a Senate aide familiar with the hearing said. The app industry is still an emerging one and presents unique challenges on privacy, such as how best to display company policies on smartphone screens, and many developers may not even be aware of how their apps interact with privacy law.

Representatives from Apple and Google will be asked how the firms, as the companies that produce the platforms for apps, can provide the best choices and privacy notices for customers.

Bret Taylor, chief technology office at Facebook, will also speak before the panel. The social network produces one of the largest location-based apps on the market.

Privacy is getting a lot of attention on the Hill this session. Last week, Apple and Google were grilled on their privacy policies regarding geolocation data by the Senate Judiciary privacy subcommittee. There are also several bills on online privacy, including a comprehensive “Online Bill of Rights” from Sens. John Kerry (D-Mass.) and John McCain (R-Ariz.), and a Do Not Track Kids bill from Reps. Edward Markey (D-Mass.) and Joe Barton (R-Tx.) unveiled last week.