Facebook CEO Mark Zuckerberg on Wednesday commented on the massive, deepening data harvesting scandal his company has been embroiled in since last Friday. From a report: “We have a responsibility to protect your data, and if we can’t then we don’t deserve to serve you. I’ve been working to understand exactly what happened and how to make sure this doesn’t happen again,” he said. The scandal — involving the illicit collection of data from 50 million Facebook users, and its later use by Trump campaign analytics vendor Cambridge Analytica — has helped chop off nearly $50 billion in value from Facebook’s market cap since last Friday, led to calls from US lawmakers for Zuckerberg testify before congress, and raised eyebrows at the U.S. Federal Trade Commission, which is now probing the company. Speaking of things Facebook plans to do to ensure that this mess doesn’t repeat itself, Zuckerberg added, “First, we will investigate all apps that had access to large amounts of information before we changed our platform to dramatically reduce data access in 2014, and we will conduct a full audit of any app with suspicious activity. We will ban any developer from our platform that does not agree to a thorough audit. And if we find developers that misused personally identifiable information, we will ban them and tell everyone affected by those apps. That includes people whose data Kogan misused here as well.

“Second, we will restrict developers’ data access even further to prevent other kinds of abuse. For example, we will remove developers’ access to your data if you haven’t used their app in 3 months. We will reduce the data you give an app when you sign in — to only your name, profile photo, and email address. We’ll require developers to not only get approval but also sign a contract in order to ask anyone for access to their posts or other private data. And we’ll have more changes to share in the next few days.”

There is no explicit apology in Zuckerberg’s comment today.