From: Louis J Boyd <boyd>
Subject: Re: exploding gas cans!
Date: 20 Nov 1996
Newsgroups: misc.rural

Michael Sloane <msloane@postoffice.worldnet.att.net> wrote:
>bartermn@epix.net wrote:
>>
>> Both Ford Motor Company and Standard OIl Company have published technical
>> bulletins warning of an unanticipated hazard associated with plastic bed
>> liners installed in pick-up trucks. Several incidents have demonstrated
>> that these bed liners insulate static charges generated in objects placed
>> in the beds and keep them from grounding.
(snip)

>While have no doubt what you are writing may be partly true, I know that
>all filling station hoses for the last 25+ years have a metallic woven
>layer, which is connected to the nozzle and to the pump ground. I fail to
>see how a plastic liner would be any more insulating that the rubber
>tires that the truck rides on. And how would you "place them on the
>ground and away from people" and still >hold the nozzle? Now if you are
>using a farm tank with a plain rubber hose and antique nozzle, you would
>definitely have a problem...
>
>Mike Sloane (msloane@worldnet.att.net)

I haven't heard about the explosion problem, but the "rubber" in tires is not
a good insulator.  A car or truck sitting on concrete will usually have a
resistance to ground of less than 100 megohms which is low enough to quickly
drain static charges. Many plastics have resistivity many magnitudes higher
than tire rubber. The explosion could occur just as the pump nozzle is
touched to a nearly empty metal gas can which has been carried in a well
insulated bed. It only takes a tiny spark in the air/gas mixture near the
container opening.  If the can is charged and the nozzle is grounded the
spark has a place to jump.  Using >plastic< gas cans should eliminate the
problem as there is nothing to conduct sufficient current to produce ignition.

A simple cure with a metal can in a plastic bed is to hold the can with one
hand while holding the pump nozzle with the other.  A human is quite
conductive and will drain any static charge in microseconds.  I doubt that
will ever be the published solution.