I don’t know what kind of blanks they use, but outside of putting in contact with the body I can’t see how it could cause a fatal injury. Had to be a live round.
Certainly, Mr. Baldwin’s kind and generous nature didn’t play a part.
Bruce Lee was killed by a movie mishap with a firearm. They use rounds with the bullet attached in the gun in some scenes so the gun appears loaded. In the Bruce Lee incident, they removed the powder from the cartridge, but not the primer, someone fired the primer which drove the projectile into the barrel where it lodged. They then replaced those rounds with blanks for realistic gunfire sound. When the first blank went off it went off with enough pressure to propel the bullet out of the barrel which struck and killed Bruce Lee. I’m guessing this will turn out to be something like that.