The lawmakers sent letters on Monday to Apple (AAPL) CEO Tim Cook and Larry Page, CEO of Google parent Alphabet (GOOG), asking the tech giants to explain their data collection practices.

Recent data privacy blunders by Facebook (FB) as well as alleged Russian meddling of the 2016 presidential election has raised concerns by politicians that tech companies fail to safeguard user data.

Additionally, lawmakers worry that these companies are not transparent about how they share user data with third-party firms as they collect people’s data to improve their own technologies and grow their businesses.

In the letter sent to Alphabet’s Page, the lawmakers asked that the company address recent media reports that exposed some of Alphabet’s data practices. Last week, for example, the Wall Street Journal reported that Google allows some third-party organizations to access user emails. Google said in 2017 that the company would no longer scan Gmail messages for advertising purposes.

Some of the questions lawmakers want Google to answer about its email policies include:

How many outside software developers, or third parties, are permitted to access user’s email contents with or without consent on Gmail?

What restrictions, if any, does Google place on how data from Gmail users may be used?

What additional steps, if any, are taken by Google to verify that the activity of companies granted access to user’s email contents meets Google’s terms of service?

In their letter to Apple’s CEO, the lawmakers want to know more about the company’s data-collection practices related to its flagship iPhone. The House representatives want to know if Apple collects and stores user information “through a different data-collection capability” even if people disable location-tracking services on their iPhones.

Lawmakers also want to know if people’s iPhones collect audio recordings without their consent and if Apple could “control or limit the data collected by third-party apps available on the App store.”

The House members also point to Cook’s various public comments about Apple’s data privacy practices in relation to competitors like Google and Facebook. They referred to Cook recently saying that Apple “felt strongly about privacy when no one cared,” but then pointed out that Apple lets users download Google and Facebook apps from its online store, which is significant because these services and others are “contradictory to Apple’s values.”

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The implication that Apple should bar Google and Facebook apps from its online store is a sensitive one. Some lawmakers would likely accuse Apple of unfair business practices if it removed competitors from its app store.

Fortune contacted Apple and Google for comment and will update this story if they respond.