Viton is a synthetic rubber material (a fluorelastomer) used, for example, in some engine gaskets. Stories have been circulating around the world about horrendous injuries that have occurred to unsuspecting people coming into contact with the breakdown products of fluoelastomers when a vehicle has been involved in a fire. Every few years these get resurrected and a new panic breaks out so, hopefully, this will set the record straight.
As with many urban or industry myths, there may be an element of truth that makes the story more believable. In this case it goes back to 1981 at the National Nuclear Corporation in Risley (UK). An experiment was been carried out to see what happens when a Viton O ring was heated to about 400 Celsius in sealed test rig. When the worker dismantled the apparatus a clear liquid was ejected under pressure very close to his fingers. This led to discomfort and an untreated deep-seated burn developed over a period of days – eventually leading to amputation of part of his finger. The incident was investigated by HSE and, on repeating the experiment it was shown that hydrofluoric acid (HF) was produced (from hydrogen fluoride gas in presence of water).
It causes:
But it is readily treated by the use of calcium gluoconate gel (See INDG 307 Hydrofluoric acid poisoning). As unfortunate an incident as this was, it would probably have been forgotten except that some ‘well meaning’ individual produced the following warning notice, which found its way around MVR facilities, Top Gear, the national press and the emergency services:
Fluorolastomec or veton, by its other name, is a material that is being used to make brake seals and fuel pipes and possibly other rubber/plastic substitutes in motor vehicles by vehicle manufacturers.
This material becomes dangerous after it has been burnt, i.e. vehicle fire. The material melts into a highly corrosive acid, which if it gets on to the skin cannot be removed - the only treatment is amputation. This melted state will remain dangerous for a minimum of two years, only professional de—contamination will remove it safely.
Please remember this for your own safety, if you are dealing with a burnt out vehicle, always use gloves.
Remember amputation is the only treatment - there is no second chance with this chemical
Electronic ignition modulesPlease remember also the modules have inside them a chemical which if it comes into contact with your skin can cause cancer. Never open them and if they are damaged by fire or accident and are split, then be very careful.
Once a story spreads, new elements sometimes get added to make it more dramatic. In this case, rumours spread that an RAC Patrol man working on a burnt out vehicle had HF instantly absorbed through his skin leading to the loss of his hand and arm. It seems the more gruesome the story, the more people believe it!
If fact, this is all nonsense – there is no verifiable incident related to HF from burnt out vehicles anywhere in the world. And for fairly good scientific reasons. Hydrogen fluoride is a gas and, in the event of it being produced from a fluoroelastomer in a fire, it would disperse very quickly with the flames. It also needs water to produce hydrofluoric acid but if you put out the flames with an extinguisher you also dilute and wash away any acid. It seems it is rather difficult to reproduce the 600 psi, sealed-vessel conditions of the laboratory in a vehicle fire.
It makes sense to wear gloves to stop getting you hands dirty when dealing with burnt-out vehicles, so even if there was the tiniest chance of HF being present, you would be protected.
