The four man construction crew had just started working for the day, putting a wooden joist into place to support the first floor of a new home. Officials said somehow the beam fell onto the face and head of man tossing him and the beam to the basement floor.
Careflight was called and took the critically injured man to Miami Valley Hospital.
Authorities said the beam that fell on the 25-year-old man was six inches wide, 30 or more feet long and is estimated to weigh 500 to 600 pounds.
The basement of the home was fully finished. The beams were being used as the base of the first floor living quarters.
Benjamin Ward is listed in critical condition. Deputies in Clark County said they believe the construction company building the house is owned by his brother, and his brother was one of the individuals who called for help.