By the 1990s, the gas chamber had become unpopular in the United States. It never became as popular as execution by electric chair or (more recently) lethal injection. When Donald Eugene Harding was executed in Arizona in 1992, witnesses described his death as "violent" and an "ugly event". The last prisoner to be executed in the gas chamber in the United States was Walter LaGrand, in Arizona in 1999. All states that still have the death penalty use lethal injection.