Petrol and Safety

Petrol is probably the most dangerous chemical that most people will encounter from day to day.

This is because it is both carcinogenic and flammable.  The carcinogenicity is mainly the result of benzene which is such a common chemical in crude oil, it would be both impractical and uneconomical to attempt to remove it.

Probably a bigger problem however is its flammability.

For years the myth has been around that mobile phones can ignite petrol.  There have been reports floating around the Internet to be effect that Shell has issued an official warning about using mobile phones whilst filling your car with petrol.

As it happens, these reports are myths.  I’ve searched high and low but have been unable to find any such reports directly from Shell.  And, of course, mythbusters famously dealt with this myth.  It must be said, however, that the myth busters treatment was not conclusive.  This is simply because they would have to have tested every mobile phone in existence before they could conclusively say that a mobile phone could not be an ignition source.

Certainly, if it was ever true, it was only true of the older, higher powered analogue phones that have now disappeared.

In any case however there is a much more real danger posed by the flammability of petrol – static electricity.

When a metal object moves through the air, it picks up static electricity.  Like cars, planes, and zeppelins (but that’s another story).

So when you pull up at a service station and hop out of your car, it is holding a charge because it is electrically insulated from the earth by its rubber tyres.  And you are holding a charge as well.

When you put the nozzle into the car, this earths the car.  And it sure would earth you as well.  But if you hop back into the car, particularly if it is a dry day and you are wearing synthetics like nylon, the action of you rubbing against the car seat can restore static electricity to your body.

If you then go back and out to a running pump, like this girl did, a spark can jump between you and the petrol nozzle if that’s the first thing you touch, with predictable results.

So the lesson is, if you hop back into your car while you are refuelling, when you hop out of the car touch your hand against the side of the car to earth your body before you go anywhere near the fuel pump.

But of course, none of this is an issue with diesel, as it is non-flammable.

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