In the United States
In the United States, prisons have used gas chambers to execute prisoners who were given the death penalty. The first person in the United States to be executed in a gas chamber was Gee Jon. This was in a prison in Nevada, in 1924. The government of Nevada did not want to use an electric chair, and thought hanging was cruel and inhumane.
By the 1990s, the gas chamber had become less popular in the United States. People began to think that it was too painful of a way to die. When Donald Eugene Harding was executed in Arizona in 1992, witnesses described his death as "violent" and an "ugly event".
The last person to be executed in the gas chamber in the United States was Walter LaGrand. This was in Arizona in 1999. Now, most states that still have the death penalty use lethal injection.
However, in April 2015, Oklahoma became the first state to approve using nitrogen gas to execute people in gas chambers. They approved this after it took over an hour to execute Clayton Lockett by lethal injection.