Idaho’s death row inmates can be shot by firing squad if lethal injection is not possible, under a law approved by the state legislature on Monday.

The text, approved by a vote of 24 to 11 in the conservative state Senate, now remains to be signed off by the governor.

Idaho will become the fifth US state to legalize the death penalty, following Utah, Oklahoma, Mississippi and South Carolina, according to the Death Penalty Information Center.

Since 1976, when the brief moratorium on capital punishment in the US ended, two men and one woman have been executed this way, all in Utah (west). The most recent execution by firing squad dates back to 2010.

US states that use the death penalty are finding it increasingly difficult to procure the chemicals needed for executions by injection because of resistance from pharmaceutical companies that do not want to be associated with capital punishment.

Killing by firing squad in Idaho will not be authorized unless the use of lethal injection is impossible.

The powerful ACLU civil and civil rights organization criticized the adoption of the law, a “disgusting” development in its opinion, calling the text “archaic”.

“The firing squad is particularly gruesome (…) such executions leave an indelible mark on everyone involved,” he commented in a press release issued by the ACLU’s Idaho branch.

People who are shot by firing squad suffer “extreme pain” and a “torturous death,” the organization added, citing experts.