An explosion occurred and was followed by fire in a liquefied combustible gas storage and supply facility. The pump room, electric control room and a part of the regeneration workshop were destroyed. One employee sustained injuries and another one was in a state of shock. Material damage was assessed at 350,000 DM. After investigations the gas pipelines and other underground protective electrical sheaths were not found to be airtight due to the presence of rust. Consequently, the gas infiltrated into the ground. Given the weather conditions (soil frozen at that period), the gas could not diffuse into the air and thus travelled through the leaking pipes below the building to reach drainage areas not connected to the sewage network. An explosive mixture was gradually formed and spread to the surrounding areas comprising rest rooms and wash rooms where even lighting a cigarette could cause the cloud to explode. Equipment and related devices (hoses in liquid or gas phase, loading arm, etc.) were replaced in the product transfer area with tanker trucks. A gas detection device controlled by an automatic emergency shutdown mechanism was also installed.