Eighteen-year-old Ephrata resident Randall Hoover has been charged with recklessly endangering another person.
Police say he is related to the victim, 5-year-old Andrew Hoover.
The boy was fatally shot in the head on an Earl Township farm Sept. 5. Investigators say a 6-year-old boy fired the gun.
Police said Monday that Randall Hoover failed to secure the weapon and ammunition in a way that would have kept the children from accessing them.
It was not immediately known if Hoover had an attorney and a telephone number for him could not be found.