Andy, do you have any scientific evidence for your claims? Once mercury is inside the human body it is either stored or excreted - in order for it to be excreted it MUST travel through plasma/renal tubules/biliary and/or GI tract and by the metal's nature (a potent oxidant) that mobilization causes symptoms. If these heavily exposed workers exhibit no symptoms of poisoning whatsoever, it is more likely than not that their organs are incapable of mobilizing and excreting the toxin - they are simply storing it....it is not getting drunk that hurts, it's the morning after. As far as your alcohol analogy, there is a dna sequence that encodes the enzyme that detoxifies alcohol, and some can produce more of it than others, but as far as mercury is concerned, even if, say, you had super high levels of glutathione and/or metallothionein, for example, the mercury would still cause symptoms as it was leaving the body. My guess is that these "healthy" workers have tremendous INTRAcellular body burdens of mercury but probably die of serious disease that mainstream medicine does not attribute to the toxin.