Lead fumes are not good to breath. Period. It will get into your blood steam from your lungs, and you don't need that stuff in your lungs, either.
Just do your lead melting outdoors or in a well ventilated room, with a fan blowing over the top of the pot, to take the fumes away from your face. If you are doing a lot of casting, you will want to buy some of those styrofoam masks at the hardware store.
You also want to change clothes, and take a shower after handling lead for any length of time, so you get the lead dust off your skin, and out of your hair. Because lead is so hot, its not difficult to rmember to keep your face away from the top of the lead pot when casting, or pouring. I did a lot of casting of .30 cal, .32 cal, .357. cal., and .45 cal. bullets for my father when I was a teenager, in a basement without the best of ventilation. I worked for about an hour, and then stopped to go get some fresh air, and clear my lungs. Knowking what I know now, I would not have let Dad set up the casting equipment in the basement and we would have done it instead in the garage. It would have been colder, but it also would have been safer. We had some space heaters we could have used to keep our feet warm, and that is what would have been the most comfortable to us. Our hands would stay warm near the lead pot.
Oh, elevated blood lead levels are reversible in Adults. I had two friends who were range officers at our local Police academy, who were found to have elevated lead levels, and taken off the range to teach classroom work. A year later, they were both tested again, and the lead levels were almost non-existant, well below any level that would have caused concern. The same was found when their chest X-rays were examined for lead in their lungs. The lungs were " pink " and free of lead. The body cleaned out the lungs on both men. The same thing is found on long term smokers, after they quit. A year later their lungs are as clean as any adult who has never smoked in his life.
