lead
This will be a short one, but probably the most important article I'll ever write.
The problem
People who own or use firearms are at elevated risk of lead poisoning, or, worse, poisoning younger people they know. Lead can only accumulate in the body, no amount is safe, and the damage it does is pretty tragic.
The scare tactics
Please let me scare you here. Scared is the appropriate emotion until you're sure you're mitigating the risk. Then there's no need to worry.
Let's start by mentioning that OSHA, NIOSH and the CDC recommend bagging your lead-exposed clothing before getting into your car, washing them in a separate load, and then running the washing machine cycle with no clothes in it before washing other clothing.
OSHA recommends that those who work around lead remove their exposed clothing before getting into their family car or home, putting it into a plastic bag, and washing it in a separate laundry load. The CDC says "After clothes are washed, the empty machine should be run through the wash cycle to remove any lead dust."
Why? Because children absorb lead four or five times more readily than adults, their bodies don't eliminate it as well, and blood lead levels are a sum of our lifetime of exposure.
Bullets contain lead. Some bullets are jacketed with other metals, which reduces exposure when handling the unfired cartridges, but other bullets have exposed lead. Twenty-two long range ammunition is the most common way to come in contact with exposed-lead ammunition. You can see the lead, and when you handle it, you can see lead on your hands. If you wash it off promptly, it's no big deal for adults, but children are a different story
Lead poisoning is so common amongst older generations (there was lead in gasoline, and therefore it was spread all over everything) that some scientists wonder if our ideas of aging itself are incorrect. (find the article)
This is why shooting ranges never allow eating, drinking, or smoking, but I've never seen a single sign saying those rules are about lead exposure.