Hey, that experiment you're talking about sounds familiar. Yes, it's safe. Whether it's Heme or non-heme iron, chelated or not chelated, it's been used in cereals, especially baby cereals, baby formula's, etc. for a long time. The absorption rate of different types of iron will vary but if you were to take 3 mg of heme iron and 50 mg of non-heme iron you end up with about the same absorption. It's balanced out by just using higher mg's of the non-heme. Fewer people use them now, but a lot of people used to get their iron from iron cooking pots and skillets.
One reason it's added to baby formula is because fewer women are breast-feeding. The iron in breast milk is better absorbed, plus a normal healthy baby (if it's full-term) has enough iron stores to last maybe up to 9 months. But if the baby's not breast fed, they have to get the iron from supplements. When they get old enough for solid food, they're usually pretty picky and won't eat the good stuff that has natural iron in it, plus some of them drink too much cow's milk. When they reach the teen years, boys (and girls) who are athletic will need more iron, and girls especially need extra iron when they reach puberty. There's more anemia in girls and women because of our periods and most of us don't eat enough foods that are high in iron. Whew! That's just the short list! LOL
My body doesn't properly absorb iron, so I take supplements in the form of ferrous sulfate for my anemia. Oh joy.