In a clinic, a liquid oxygen leak occurred around 3 pm on a 3,000-litre tank (i.e. 3.41 tonnes). This new tank had been installed 48 hours prior to replace a 1,200-litre capacity (1.36 tonnes) and was scheduled for service start-up as of the following day, while waiting for network hook-up. On 24th June, a check valve failed in the capacity subsequent to high heat and excessive tank filling: the safety valves opened, thereby freeing the oxygen. Escaping white smoke worried neighbours as well as clinic personnel, who alerted fire-fighters. The capacity alarm tripped, notifying the remote monitoring control room overseen by the subcontractor assigned to manage medical gases. While awaiting arrival of the subcontracted technician, fire-fighters delimited a safety perimeter and prohibited the use of any hotspot. During its escape, the liquid oxygen froze the safety valve; fire-fighters remained onsite until the valve heated back up, eventually leaving the scene at 9 pm. The operator modified procedures: in the event of a tank change, the replacement and hook-up of new equipment would be conducted within the same day.