LUCASVILLE, Ohio -- Ohio has executed a killer through the first U.S. lethal injection using a single drug, a longer but supposedly less painful method than previous executions that required three drugs.

Kenneth Biros (BY'-rohs) was pronounced dead at 11:47 a.m. EST Tuesday, about 43 minutes after he entered the death house at the Southern Ohio Correctional Facility in Lucasville.

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Ohio changed from three drugs to a one-drug method after a failed attempt at putting a different inmate to death in September. The new method uses a drug common for euthanizing pets.

Other states still use a combination of three drugs.

Biros was sentenced to die for killing a woman in 1991.