Your body is pretty awesome at regulating iron. It only absorbs as much as it needs from the diet (if you know anyone who’s taken iron pills they’ll complain about black sticky stool, as most of the iron in the pills isn’t absorbed by the body). If you lose blood by bleeding, then your intestines know to gather more iron from your next meal. So for the most part, you could be chowing on iron filings all day and not over dose on iron.
The exception is for some people with a condition called haemochromatosis (which tends to appear in middle aged men, and is somewhat common in Ireland. Also, it runs in families). This is a mutation in the genes that stops you only taking in as much iron as you need and causes your intestine to absorb as much iron as it can. This built up iron is stored in the liver where it causes a lot of damage and eventually in the skin. The cure? Get regular pints of blood from these people and reduce the iron in their diet.