First U.S. execution by nitrogen gas would cause "painful and humiliating death," U.N. experts warn

Calls continue to mount for officials to again halt the execution of a death row inmate in Alabama, who is scheduled to be put to death later this month using nitrogen hypoxia — a controversial method that international human rights experts have denounced for its potential to cause severe and unnecessary suffering.

"We are concerned that nitrogen hypoxia would result in a painful and humiliating death," said a group of experts in a statement issued Wednesday by the United Nations. The experts — Morris Tidball-Binz, Alice Jill Edwards, Tlaeng Mofokeng and Margaret Satterthwaite — are part of the Human Rights Council's special procedures program, where independent specialists work on a volunteer basis to investigate and advise on human rights issues across the world.

The human rights experts have appealed directly to U.S. federal authorities as well as authorities in Alabama, where they asked for a review of the state's execution protocol, according to the U.N.  Alabama is one of three U.S. states that allow nitrogen hypoxia as an alternative means for execution, alongside Oklahoma and Mississippi, although the Alabama execution would be the first in the country to actually happen using the method.