In the underground parking lots with artificial ventilation, toxic or dangerous conditions can be created.
Petrol vapours (C6H14 – C8H18): petrol is usually a mix of paraffin hydrocarbons like hexane and octane in variable proportion, and its vapours can spread in a parking lot because of a broken car tank. Even a small quantity is dangerous because of the high flammability of this substance.
Carbon monoxide (CO): it is one of the first products of combustion of internal combustion engines. In a place where many vehicles are parked, their contemporary movement can engender toxic atmospheres.
C6H14 – C8H18: Gasoline is extremely flammable, even by a simple spark
CO: carbon dioxide is a compressed colourless, odourless, tasteless and poisonous gas. Even short exposures to carbon dioxide may reduce oxygen concentration in brain so the victim falls unconscious and dies.