Princess Margaret Hospital said unidentified gas was reported at around 9am on 16 September 2026 at the Department of Pathology on 13/F of Block G. The hospital activated contingency measures, notified the Fire Services Department and the Police, and arranged for approximately 200 staff working at Block G to leave. Two staff members reported feeling mildly unwell but did not require medical treatment.

The hospital said it was confirmed safe after an inspection with the Fire Services Department and the Hong Kong and China Gas Company Limited, and staff were arranged to return to their working locations. The affected floors in Block G resumed normal service at around 10am that day, and emergency services were not affected.

The hospital said it was very concerned about the incident and confirmed after a detailed investigation that there was no gas leakage. It said it would review the storage, handling and disposal of chemicals to ensure compliance with Hospital Authority guidelines and would support staff in need. The incident was reported to the Hospital Authority Head Office through the Advance Incident Reporting System.