"Tank cleaning" truck working while pumping gas - potential "bad gas" problem?

I don't know what the truck was doing, but as for "bad gas" (which sounds like a medical complaint to me!!), from snopes.com: Tips on Pumping Gas

You also have to consider a typical forecourt will have several tanks, further reducing the likelihood that the pump you're using is fed from the very tank they are re-filling.

 

"And again, one has to consider the trade-off. On the (probably infrequent) occasions when you arrive at a gas station at the very same time a tanker is filling the station's tanks, is it really worth the time and expense to leave without filling up and drive off to a different service station just to avoid something that likely isn't much of a concern in the first place?"-snopes

I like snopes as a website, good place to kill some time and get information, but sometimes they can be frustratingly, sit on the fence like.

So basicly they are saying, it could happen, it does stir up sediment, but don't worry "most" gas stations have filters and cars have filters?

I live in the suburbs so finding another gas station is never that big of an issue, so I guess my answer to the above quote is YES, it's worth it to me to just go to another gas station.

If I'm on bone dry and/or stuck in a rural area or highway with little choice, I'll fill up, otherwise...even if the risk is minimal, and I believe it is, why take it?

To the OP, if I was filling and then noticed a tanker, I wouldn't sweat it. For me it becomes something I would avoid if convienent to avoid, but not sweat if I don't have a choice or it just accidently happens.

 

It may have been cleaning the space between the double walls of the tank.

Tom