Mississippi may be looking to the history books for how it will execute death row prisoners.

Lawmakers are considering adding firing squads, electrocution and gas chamber to approved execution methods, The Associated Press reported.

The move is to fill a gap if a court blocks the use of lethal injection.

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House Bill 638 was introduced after lawsuits were filed that claimed that the lethal injection drugs are cruel and unusual punishment and are therefore unconstitutional.

Mississippi last executed a prisoner in 2012 and has not been able to secure the drugs it once used, The AP reported.

There are 47 people on Mississippi's death row.

Only Oklahoma and Utah have the option of firing squads. Eight states can use electrocution. Five have gas chamber options and three still can use hanging.

For a breakdown of how states can execute death row prisoners, click here.