Montgomery, Ala. ? Gov. Don Siegelman signed a law Thursday making lethal injection the primary method of execution in Alabama, leaving Nebraska as the only state exclusively using the electric chair.

Beginning July 1, condemned inmates in Alabama will die by injection unless they choose the electric chair.

Siegelman said the change was a precaution in case the Supreme Court ruled the electric chair was cruel and unusual punishment.

Prosecutors backed the change to make sure capital punishment remained legal in the state.

The Supreme Court earlier this month blocked the execution of Alabama death-row inmate Gary Leon Brown, convicted of stabbing a man to death in 1987.

His appeal contended, in part, that the electric chair was cruel and unusual.