Richard Glossip death row Oklahoma
Death row prisoner Richard Glossip has lost an appeal and faces execution

UPDATE : Oklahoma death row inmate Richard Glossip's lawyers made a final plea Tuesday (September 29th, 2015) to the U.S. Supreme Court asking for a stay on his execution -- a day after the state's highest criminal court rejected new hearing. Glossip is scheduled to be put to death by lethal injection on Wednesday afternoon on September 30th.

Richard Glossip could be the first American to be executed by nitrogen gas. This follows his appeal, together with two other prisoners, against the use of the controversial lethal injection drug, Midazolam.

In April the Governor Mary Fallin of Oklahoma signed a law which allows death row prisoners to be executed with nitrogen gas, as alternative method to lethal injection. If the Supreme Court rules in the prisoner's favour, the state is prepared to gas Glossip.

Midazolam is used in the three-drug cocktail used to execute death row prisoners in Oklahoma. A sedative, it is supposed to render the prisoner unconscious so they are unable to feel the effects of the two other drugs which kill them.

However, last week the US Supreme Court heard heard that Midazolam is unable to render prisoners unconscious. This has led to prisoners' becoming distressed and their executions being prolonged.

Robert Dunham, executive director of the Death Penalty Information Centre, told Sky News: "You've got inmates who are conscious, you've got inmates who are gasping. One description is that an inmate was flopping around like a fish against the restraints."

Gassing vs injections

The Supreme Court will make a ruling on the use of the drug in June. Oklahoma might then go ahead with Glossip's execution using nitrogen gas, although his lawyers are continuing to mount challenges on his behalf.

Nitrogen is an inert gas that is not normally toxic to humans – it makes up 78% of air. However, if there is a limited amount of oxygen available, it kills by asphyxiating people.

The use of nitrogen as a human form of execution was first advanced in the US in 1995. The execution method is likely to consist of a prisoner being forced to inhale nitrogen by wearing a mask over their head neck which is supplied with pure nitrogen.

In theory, the victim will quickly fall unconscious due to a lack of oxygen, and then will slowly die from lack of oxygen in the air.

Nitrogen gas is used to euthanise animals. As nitrogen is an inert gas, it is believed that it does not cause a painful death. However, this has only been tested through observation of animals being euthanised – usually chickens.

Questionable conviction

Glossip, 51, has been on death row since he was convicted of first-degree murder 17 years ago. He was convicted on the testimony of a single witness and has always maintained his innocence. If the execution goes ahead he will be the 196th person to be put to death by the state of Oklahoma.

Prior to arrest and conviction, Glossip was the manager of the Best Budget Inn in Oklahoma City. The motel's owner, Barry Van Treese, was beaten to death with a baseball bat in January 1997. Justin Sneed, a handyman who worked and lived at the hotel, confessed to the murder. Prosecutors alleged Glossip feared losing his job and recruited Sneed to kill his boss. Sneed testified that Glossip promised him $10,000 to commit the crime. Both men were convicted of first-degree murder, but in exchange for his testimony, Sneed received a life sentence without parole, while Glossip received a death sentence.

A judge told Glossip that if he admitted his involvement in Van Treese's death, he would be sentenced to life in prison and eligible for parole in 20 years. Glossip said he refused to perjure himself by admitting to something he did not do.

In December last year Glossip went on a hunger strike. Several anti-death-penalty advocates have supported his case, including Sister Helen Prejean, the advocate made famous by the memoir Dead Man Walking.

Glossip has has four children: Christina, 35; Erica, 32; Tori Lynn,28; and Richard Jr., 26, as well as two grandchildren, aged 14 and 8.