Part of the Apple Park campus in Cupertino was evacuated after first responders discovered an envelope containing a white powder substance.
According to the incident report from the Santa Clara County Fire Department, a fire alarm and hazmat response had been activated at Apple's headquarters shortly after noon local time.
NBC Bay Area reports emergency personnel has since concluded that the situation is under control, and employees have been allowed to return inside. What the substance could have been is unclear.
According to an email acquired later in the day by The Verge, Apple informed staff at Apple Park that "authorities concluded that there was no presence of hazardous materials." Campus operations have returned to normal, and "all sections are open," the email says.
CEO Tim Cook, in an email to Apple employees obtained by The Verge, announced that Apple will begin phasing in its planned hybrid work program on Apr. 11, bringing staff back to the office one day a week to begin. Apple first unveiled its plans for a hybrid work pilot in November.
Employees will come in twice a week in the third week of the trial, according to Cook, with the full hybrid pilot - where workers would come into the office Monday, Tuesday, and Thursday and work "flexibly" on Wednesday and Friday - starting on May 23.. Cook said that the timing may differ from office to office depending on local factors.
"For many of you, I know that returning to the office represents a long-awaited milestone and a positive sign that we can engage more fully with the colleagues who play such an important role in our lives," he wrote.
"For others, it may also be an unsettling change. I want you to know that we are deeply committed to giving you the support and flexibility that you need in this next phase."
Cook also mentioned that the hybrid plan allows for up to four weeks of remote work each year. In the email, he also stated that Apple's retail locations will no longer require masks "over the next few weeks."
"In the coming weeks and months, we have an opportunity to combine the best of what we have learned about working remotely with the irreplaceable benefits of in-person collaboration," Cook added.
Throughout the ebb and flow of coronavirus cases and restrictions, Apple has revised the return-to-work date multiple times. Most recently, Apple "indefinitely delayed" the office reopening, which had been set for Feb. 1.
