Delta CEO Ed Bastian said the recent global tech outage cost his company $500 million after the airline suffered major flight delays and cancellations.

“This cost us a half a billion dollars,” Bastian said Wednesday on CNBC’s “Squawk Box.” 

“Over a period of five days, between not just the lost revenue, but the tens of millions of dollars per day in compensation and hotels and — we did everything we could to take care of our customers over that time frame,” Bastian said.

While multiple airlines had issues with technology around the time of the July 19 outage, Delta faced large numbers of cancellations in the days following.

The mass cancellations sparked scrutiny from the Department of Transportation, with Transportation Secretary Pete Buttigieg saying officials aimed to ensure Delta was “following the law and taking care of its passengers.”

The global outage was linked to an update from cybersecurity company CrowdStrike that crashed computers running Windows software. While the cyber firm rolled out a rapid fix, it took long periods for impacted customers to recover.

Thousands of Delta flights were canceled or delayed in the days following the outage.

When asked Wednesday about potentially suing over the outage, Bastian told CNBC, “We have no choice.”

“If you’re gonna be having access, priority access, to the Delta ecosystem in terms of technology, you’ve gotta test this stuff, you gotta… you can’t come into a mission-critical, 24/7 operation and tell us, ‘We have a bug,’” he said. “That doesn’t work.”

In a statement emailed to The Hill, a CrowdStrike spokesperson said the company was “aware of the reporting, but have no knowledge of a lawsuit and have no further comment.”

A spokesperson for Microsoft declined a request for comment.

Delta announced July 24 that its operations had almost fully returned to normal, with zero canceled mainline flights.

Updated: 4:34 p.m.