A story in USA Today last year regarding bat safety had this quote “an American Legion Baseball study in 2005 found no substantial scientific proof that wooden bats are safer than metal bats.” I don’t know anything more about it than that though.
As a kid...we used only wooden bats. I sat there once...barely 30 feet from the batter when he swung and the bat broke. The broke end came my direction and fell around five feet from me. I sat there and thought...man, it’d be great to have steel bats that wouldn’t break. Maybe I was wrong though.
It’s very rare, if it you get hit just right in the chest, with a baseball or a fist, it stuns the heart into stopping. It’s tragic, but an unavoidable risk of being a human being. The parents ought to sue God, nature, gaia or Darwin, according to their faith.
The science is pretty clear, balls do leave metal bats with more velocity than when hit with a wooden bat. Not sure what study you are quoting other than perhaps they found no conclusive evidence that this speed results in more injuries.. but there is no doubt or debate that balls do come off metal bats with higher velocities.