NASHVILLE (AP) — The Tennessee Supreme Court has decided not to hear an appeal by two death row inmates who claim that changes to the state's lethal injection procedure are unconstitutional.

The state's high court on Monday declined to hear the case brought by Stephen Michael West and Billy Ray Irick. Their attorneys argued that the state's protocol does not contain sufficient safeguards to ensure that condemned inmates don't suffocate while fully conscious, which could violate the constitutional ban on cruel and unusual punishment.

Davidson County Chancellor Claudia Bonnyman last year upheld the state's three-drug lethal injection procedure after the state Department of Correction added a new step for the warden to check that the inmate is unconscious after the first drug is injected.

No execution dates have been set for either inmate.