LXX Deut 19:5

καὶ ὃς ἂν εἰσέλθῃ μετὰ τοῦ πλησίον εἰς τὸν δρυμὸν συναγαγεῖν ξύλα, καὶ ἐκκρουσθῇ ἡ χεὶρ αὐτοῦ τῇ ἀξίνῃ κόπτοντος τὸ ξύλον, καὶ ἐκπεσὸν τὸ σιδήριον ἀπὸ τοῦ ξύλου τύχῃ τοῦ πλησίον, καὶ ἀποθάνῃ, οὗτος καταφεύξεται εἰς μίαν τῶν πόλεων τούτων καὶ ζήσεται·

If he goes into the forest with his neighbor to cut timber and swings his axe to chop down a tree, but the blade flies off the handle and strikes and kills his neighbor, he may flee to one of these cities to save his life.