Dirt in a vehicle's gas tank is sometimes transferred there from a gasoline-station fuel tank during fuel pumping. It is common for gasoline stations' fuel tanks to develop dirt and/or debris and sediment each time the tanks are refueled by fuel trucks. Dirt in fuel trucks' lines or hoses and dirty gas-station fuel tanks themselves can all be responsible for injecting dirt into a vehicle's gas tank during fueling. It's quite common for dirt that has settled at the bottom of gas-station tanks to be stirred up when fuel trucks begin refueling. This makes it easier for the circulating dirt to get transferred into a vehicle's gas tank.
Fuel-pump hoses themselves can be dirty, either from dirt that has lodged inside during fueling or from dirty outer fuel-pump housings or nozzles. When one of these dirty hoses is used to refuel a vehicle, it is common for some of the dirt to be injected into the vehicle's gas tank. Normally, these pump hoses are cleaned and maintained on a regular basis. However, poor maintenance procedures can lead to excessive dirt buildup that can easily be transferred into a vehicle's gas tank.
Dirty gasoline is an obvious contributor to a dirty vehicle gasoline tank. When gasoline is manufactured at oil refineries, it is common for small bits of dirt and/or debris to wind up in the gasoline. Airborne contaminants, dirty manufacturing machinery and even contaminated fuel detergents and/or additives can be sources for dirt that winds up in manufactured gasoline and ultimately makes its way into a vehicle's fuel tank. Although most gasoline types are manufactured in a way that ensures their overall high quality and cleanliness, it is still common for small amounts of dirt and/or various types of contaminates to wind up in gasoline.
