OGP, the International Association of Oil and Gas Producers, has issued a safety alert following the death of a worker at a construction/rig repair yard in Singapore in May this year. The worker had entered an enclosed space which was inerted with argon gas for a welding operation.
Argon does not do much which is why it is useful in processes like welding where a non-combustible atmosphere is needed to prevent fire and explosions. It can also kill, as this case shows.
Too often there is more than one casualty. The first victim is joined by those who follow attempting a rescue. About two thirds of casualties are would-be rescuers.