Apple issued the following statement concerning the incident:
Five workers at our Maiden data center were taken to a local hospital following possible exposure to fumes, which may have been released during a spill of a chemical used to clean the cooling systems. All five were discharged and will return to work tomorrow. The spill was quickly contained and poses no threat to anyone else at the facility.
While Apple did not specifically mention which chemical had leaked, local news reports indicate that it was chlorine.
The incident follows the fire that broke out in Apple's Mesa, Arizona facility last week. Thankfully, no one was injured in that incident.
Apple's Maiden, North Carolina data center generates 167 million kilowat-hours of renewable energy per year -- enough to power the equivalent of 13,837 homes. Apple granted NBC an exclusive tour of the data center last year.