An Ohio inmate, Kenneth Biros, was executed Tuesday morning using a one-drug lethal injection, a first in the U.S.

Previously a three-drug cocktail was used to put death row inmates to death.

Biros had previously argued the three-drug cocktail method could cause severe pain and could lead to problems if a usable vein couldn't be found.

Biros was sentenced to death for killing and dismembering a woman he met in a bar in 1991.