Nitrogen gas "will be administered for 15 minutes or five minutes following a flatline indication on the EKG, whichever is longer," the protocol says.

The Alabama attorney general says he believes more nitrogen gas executions will occur after Kenneth Smith became the first person in the U.S. to be executed that way.

Experts have denounced Alabama's planned execution of a death row inmate by nitrogen hypoxia — an untested suffocation method that they say could cause "grave suffering." ...

Using a meta-analysis of observations from nitrogen addition experiments, and by conducting an experiment in which nitrogen was added to a lowland forest in China's Dinghushan Biosphere Reserve ...

A court in Louisiana ruled Jessie Hoffman can be put to death Tuesday using nitrogen hypoxia - deprivation of oxygen causing suffocation.

Gov. Kay Ivey (R) set an October execution date for Anthony Boyd, an inmate alleging the state’s use of nitrogen gas is ...

The day after Alabama carried out the first-known US execution using nitrogen gas, its attorney general sent a clear message to death penalty states that might want to follow suit: “Alabama has ...

The execution of convicted murderer Kenneth Eugene Smith using nitrogen hypoxia was "textbook," Alabama's attorney general Steve Marshall said in a news conference on Friday. The execution was ...

Ohio's Republican Attorney General Dave Yost wants to restart executions with nitrogen hypoxia after Kenneth Smith's execution in Alabama.

Kenneth Eugene Smith was put to death by nitrogen gas on Thursday night, the first time the method was used in capital punishment in the U.S.