A man had to be pepper sprayed by police after becoming aggressive towards council workers.
Dozens of people were evacuated from Howden House in Sheffield city centre after a 30-year-old man became aggressive and started making threats towards staff.
Police were called to the building on Union Street at around 3.55pm on Tuesday.
Armed officers also attended the incident after receiving reports of a weapon but they were not needed, a force spokesman said.
Police took the man to hospital due to concerns for his welfare and to receive treatment for a cut on his head.
No one else was injured and no weapon was found.
Howden House reopened around an hour after police were called.