In the early afternoon, an explosion at a car wash facility kills 2 people who are washing their car. The emergency responders demarcate a danger zone and the petrol station at a shopping centre 30 metres away is closed temporarily. Initial findings indicate that the explosion occurred inside the equipment room located between the 2 car wash areas, destroying this room and propelling concrete blocks up to 5-6 metres. The room which houses electrically-powered (not gas-powered) equipment is located near 2 underground fuel tanks which supply the pumps at the neighbouring petrol station. Moreover, the car wash facility is built on a site formerly occupied by this petrol station; specifically, a row of fuel pumps used to stand very near to where the car wash facility’s equipment room was built. The closest tank lies 2 metres away. At the petrol station, initial findings reveal the absence of seal plugs to block the gauge holes in the underground tanks. In the configuration on this site, these holes open onto a manhole which is also sealed with a plug. Pipes which were no longer in use but which used to supply the petrol station’s old row of fuel pumps arrive in this manhole. Given that the fuel tanks had been filled 1 hour before the accident, a possible hypothesis is that fuel vapours had travelled through the non-plugged holes and the manhole, into the obsolete pipes, all the way to the equipment room. They could have accumulated there (small, crowded room) and caused the violent explosion which occurred, on the condition that there is a connection between the obsolete pipes and the equipment room. An investigation is carried out.