An arborist at the North Carolina Zoo was killed after toppling out of a tree during a safety drill this week, according to new reports.

The North Carolina Zoo in Asheboro worker was “engaged in an aerial rescue drill” Thursday morning, and suddenly “fell 20 to 30 feet from a tree and died at the scene,” state Department of Labor spokeswoman Mary Katherine Revels told local station FOX 8.

Authorities received the emergency call at 8:20 a.m., Randolph County Sheriff’s Office spokeswoman Amanda Varner told the station.

“The entire zoo community is deeply saddened by this loss and our thoughts and sympathies are with the family of our team member,” officials there said.

“The zoo is working closely with investigators to determine details of the incident, which was not related to any of the Zoo’s animals,” the statement said. “We will provide more information as it becomes available.”

The drill involved two arborists — one simulating a person trapped in a tree and the other performing a rescue, local outlet WSOC-TV reported.

The deceased worker’s name was not released out of respect for the family.

The Africa section of the zoo was closed to the public following the incident, and the entire park closed down early, by 2 p.m., the zoo said. The zoo was open for its normal hours on Friday.

The sheriff’s office, along with the Department of Labor and the US Occupational Safety and Health Administration, will investigate the incident, according to the reports.

Grief counselors are on hand at the zoo.