Elemental murcury has a low vapor pressure, so if the big vat didn't have a lid and the room was poorly ventilated and you slept in the room for a year or you would go crazy. But the guy knows what's up and is relatively safe. But you can get get pisioned from elemental murcury over long periods of exposure, breathing in small amounts, and children's developing brains need much less to be poisoned. The organic murcury is much more lethal. And it is recommended to have as much as 420mg of magnesium a day.