I am no expert but I do service 3 DG (dangerous goods as we call them them here in NZ) rated machines, one electric and two diesels. The electric is no problem because everything that has power on it is in a steel box of at least 12mm thickness ( a headlight weighs about 10 to 12Kg) and is almost, literally, bullet proof. There is nothing for the operator to do or mess with. Experience has shown that it is essential that they receive very regular servicing which has never shown a scary problem, because of the regular servicing and that is as it should be. The diesels however are a different storey. The problem being that the exhaust scrubbers require daily checks. These daily checks are supposed to be carried out by the operators but are quite often missed although they are quite simple. The water in the scrubber tank needs changing every day along with a check of the sacrificial anode and a check of the spark arrestor for blockage. The other problem is with the laziness of operators. The diesels are started with a portable battery in a safe area. I quite often find that some clown has wheeled the starting battery into a DG area and started the machine there!! Also occaisionally some idiot in dispatch will drive there non DG machine into a DG area! So far there have been no explosions but how long will that last? This particular factory makes spray cans and paint including engine start! How scary is that? Fortunately my work place is about 12Km from the factory. The bottom line is that at least 50% of saftey in explosive atmosphere enviroments seems to be personal education. Unfortunately a large percentage of employees seem to think they know better.