Hint: If a doctor who handles the stuff for 50 years doesn't get sick, maybe you should take note of that.
The biggest risk is during condensation of the material into a cavity prep...which means the doc is at greater risk because this is when the mercury is pushed out of the filling before it sets...with the initial set happening within 5-10min usually before the procedure is over.
That wasn't learned at dental school but in damn near a decade of practice after the fact.
I personally do not have anything against dental amalgams in most people, but I also know many dentists avoid them today simply because of the esthetics issue.
The alternative is a composite filling or an onlay/inlay.
Composite fillings have about a 5 years+ life in the mouth of most people with 10 years pushing it before it needs to be replaced. Amalgams are sturdier, last longer, and are what I would choose to out in the mouth of someone who I was convinced would not be receiving regular dental treatment and who had poor oral hygiene because of the factors mentioned earlier.
If someone has good oral hygiene and sees a dentist regularly, there is nothing wrong with composite fillings and they do look better.
COST is a major factor as well because tons of people love to talk a good game, but the truth is, most will see the bill for an inlay/onlay, notice the 5-800 dollar difference, notice what insurance pays and then choose the amalgam because it costs less.