Mercury alone is safe enough to handle a bit where you would be mostly worried about breathing too much of its vapor. Organic compounds of mercury on the other hand can kill you within days of a drop touching your skin.
It's pretty obvious that once the sales for the game tanked after the initial release that Bethesda just wrote the game off and reallocated the resources to other projects. There is a good amount of potential in the setting if problems were fixed and mod tools were released but a lot of the bones of the game are just bland and uninteresting.
Mercury alone is safe enough to handle a bit where you would be mostly worried about breathing too much of its vapor. Organic compounds of mercury on the other hand can kill you within days of a drop touching your skin.