On Sun, 8 Jan 2012 01:30:31 -0800 (PST), harry
wrote:

When refueling aircraft, you are supposed to connect an earth lead to
them before you start. Especially important if they have just landed.
The rubber dispensing hose is a special antistatic job too that has to
be tested regularly. It is of a resistance to discharge any static
electricity but not so low a resistance to cause a spark.
Fuel vapour is displaced out of the tank as the fuel goes in.

I know.
These were pics taken of the inside of a fuel tank *as it was being
refuelled*, with anti-static precautions in place. It was remarkable
how the whole lot didn't go up.
I presume it was nothing unusual, but still...