According to Henriksen et al. (see references), the lesson learned were:1. Under the abnormal condition of operation of the lab, the planned reduction of the total hydrogen quantity to a small 10 l bottle would have reduced the released hydrogen by 55% even in the case of complete depleted. 2. The presence of a hydrogen detector and alarm may have saved the laboratory from a severe accidental explosion. Without it, the whole hydrogen gas cylinder would probably have been released into the room, creating a 1.2 meters high gas cloud with 15 % stoichiometric hydrogen.3. The age of the hydrogen gas regulator used was difficult to determine by reading the numbers printing on the back. The age was first established after contacting a supplier. This is an important information to determine the end of life of lab instrumentation. 4. Related to point 3., there is a need for regular maintenance/check of the gas regulators . Following the incident, a service has been established.5. A pressure safety valve on the gas regulator is not a safety feature when the safety valve releases the gas into an environment that contains several ignition sources. To work as a safety feature the gas needs to be routed to a safe ventilation point. A similar event happened at a commercial facility in 05/03/2013, where a failure of the pressure safety valve occurred. One of the conclusions from the investigation was that if the safety valve shall function as a safety feature the gas needs to be released in a safe location.