Kenneth Eugene Smith, 58, was executed in the southern state of Alabama on 25 January. He had been convicted of murder in 1988.

“Alabama’s use of Kenneth Smith as a human guinea pig to test a new method of execution amounted to unethical human experimentation and was nothing short of State-sanctioned torture,” the experts said in a statement.

“The use, for the first time in humans and on an experimental basis, of a method of execution that has been shown to cause suffering in animals is simply outrageous.”

Painful death

The experts have joined the chorus of UN officials deploring Smith’s execution, including UN High Commissioner for Human Rights Volker Türk.

They had previously called for a stay of execution, noting that nitrogen gas inhalation causes a painful and humiliating death. Additionally, experimental executions by gas asphyxiation are contrary to international law.

They said Mr. Smith reportedly took over 20 minutes to die “instead of the ‘swift, painless and humane’ death predicted by authorities, who defended the use of the method despite the lack of scientific evidence”.

Witnesses reported that he writhed and convulsed on the gurney, gasping for air and pulling on the restraints.

Decades on death row

Mr. Smith had spent decades on death row after being convicted in the murder-for-hire killing of Elizabeth Sennett in March 1988. His first death sentence, in 1989, was dismissed on procedural grounds three years later.

He was tried again in 1996, when the jury voted nearly unanimously to sentence him to life in prison. However, the trial judge overrode the decision and imposed the death penalty instead.

Alabama abolished the practice of judicial overrides in 2017, yet without retroactive effects. Mr. Smith survived a botched execution by intravenous injection in 2022 that lasted hours and reportedly amounted to torture.

Ban ‘barbaric’ practice

The experts reiterated their grave concern that other US states were taking steps to use nitrogen gas inhalation as a method of execution. Calling for a ban, they reminded the US of its obligations under international treaties that uphold civil rights and prohibit cruel, inhuman or degrading treatment or punishment.

“The gruesome execution of Kenneth Eugene Smith is a stark reminder of the barbaric nature of the death penalty and a powerful moment to intensify calls for its abolition in the United States of America and the rest of the world,” they said.

About UN experts

The four experts who issued the statement are all UN Special Rapporteurs appointed by the UN Human Rights Council, located in Geneva.

Their mandates cover the issues of extrajudicial, summary or arbitrary executions, torture and other cruel, inhuman or degrading treatment or punishment, the independence of judges and lawyers and the right to enjoy the highest standard of physical and mental health.

They are not UN staff and are not paid for their work.