Here we go...
http://www.unc.edu/depts/nccsi/AllSport.htm
High school spring sports have been associated with low incidence rates during the past twenty-three years, but baseball was associated with 44 direct catastrophic injuries and track 57. A majority of the baseball injuries have been caused by the head first slide or by being struck with a thrown or batted ball. If the headfirst slide is going to be used, proper instruction should be involved. Proper protection for batting practice should be provided for the batting practice pitcher and he/she should always wear a helmet. This should also be true for the batting practice coach. During the 2005 baseball season four high school pitchers were stuck in the head with batted balls. One pitcher recovered, two were non-fatal at the time of this writing, and one died. Two injuries took place in a game, one in batting practice, and one in a batting cage. A new rule in fast pitch soft ball will require players to wear batting helmets equipped with NOCSAE approved facemasks/guards. The rule will go into effect January 1, 2006.
The number quoted go back to 1982, not all catastrophic injuries result in death or permanant injury.
Direct injuries per 100.000 participants, 1982-2005
Fatal, 0.10; Non-Fatal, 0.17; Serious, 0.20
The majority of problems from this paragraph seem clear:
1. Head first slides
2. Practice, mostly BP
3. And this includes the lively metal bat era.
I could almost see making helmets w/o face masks mandatory for pitchers, but I would still be against it.
The number of HS kids hurt by taking pitches to the face is almost nil. And if nothing else, ask your local umpires how many serious injuries have happened in their games.