The phrase "to be blown apart" means "to be caused to explode." For example, (sorry for the weird example--it's all I can think of right now, lol) if you took a gun and shot a watermelon, the watermelon might explode. We'd say, "The watermelon has been blown apart" or "The watermelon was blown apart." That's the passive form of the phrase.
The active form of the phrase is "to blow apart." So, I could say, "That guy shot a watermelon and blew it apart."