The incident occurred around 11:59 a.m. local time at one of the tech giant’s data centers in Council Bluffs, Iowa, a city just over the Missouri River from Omaha, Nebraska. Three electricians were working at a power substation near the building when an “arc flash” electrical explosion happened and engulfed them, SFGate reported.

The three workers were critically injured, suffering significant burns, according to the Council Bluffs Police Department. All were taken to nearby Nebraska Medical Center—one by helicopter and the other two by ambulance. All three were reported to be breathing and able to talk.

“We are aware of an electrical incident that took place today at Google’s data center in Council Bluffs, Iowa, injuring three people onsite who are now being treated,” Google spokesman Devon Smiley wrote in a statement to SFGate.

“The health and safety of all workers is our absolute top priority, and we are working closely with partners and local authorities to thoroughly investigate the situation and provide assistance as needed.”

The Council Bluffs facility is among the largest data centers that Google operates. The centers are where Google maintains the servers and pieces of hardware that allow its numerous services to operate around the clock.

The company has 16 data centers in the U.S., either operational or under construction. It also operates many overseas, including eight in Europe, seven in Asia and three in South America.

Newsweek reached out to Google for comment.

The incident in Council Bluffs occurred on the same day that Google’s services experienced a rare outage for many users. According to the popular online tool, DownDetector, reports of issues with Google spiked at about 9:30 p.m. Monday, with more than 40,000 users reporting issues. As the issue took hold, users took to social media, reporting that they were being served “500” internal server errors when attempting to search on Google.

“Google is down,” writer Adario Strange tweeted in response to the outage. “Restart the apocalypse.”

It is unclear if the outage was related to the electrical incident in Iowa. Google has not released any statements linking the two events as of Tuesday morning. It is unlikely that there is any connection, given that the explosion happened nine hours before the outage, with DownDetector showing no uptick in issues when it occurred.