Death row inmates appeal after botched execution

WASHINGTON - Three US death row inmates have filed new appeals seeking to stop their executions citing apparent suffering by a prisoner put to death in a botched procedure in Oklahoma last month.

Robert James Campbell, who is due to die in Texas on Tuesday, sought a stay on the grounds that he may be subjected to an execution as painful as the one suffered by Clayton Lockett on April 29.

Convicted killer and rapist Lockett died 43 minutes after the start of the lethal injection and appeared to be in significant pain. Lethal injections normally take around 12 minutes.

US states using the death penalty face critical shortages of lethal injection drugs after European firms stopped supplying pentobarbital.

The shortage has prompted many US states to turn to compounding pharmacies to supply untested execution cocktails instead.

Campbell on Monday requested a New Orleans' court's reversal of a denial of the execution stay he has sought.

Mr. Campbell's "8th Amendment rights can only be protected if he is provided the information required to ensure a humane, non-torturous execution," his attorney Maurie Levin wrote. The eighth amendment bars "cruel and unusual" punishment.

Russell Bucklew, who is due to receive a lethal injection next week in Missouri, has argued that a vascular tumour and circulatory problems could put him at risk for the kind of suffering witnessed in Oklahoma.

"There is also a grave risk that, because of Mr. Bucklew's severe vascular malformations, the lethal drug will not circulate as intended, delaying the suppression of the central nervous system and prolonging the execution - which will likely cause excruciating pain to Mr. Bucklew," said his attorney Cheryl Pilate.

"These risks are heightened by the use of a compounded drug, pentobarbital, in the absence of any disclosure about the drug's safety, purity and potency. In fact, the Department of Corrections will not even confirm whether the drug is subject to any laboratory testing whatsoever," she said.

And Richard Poplawski, sentenced to be executed in Pennsylvania but with no date set, is appealing in a bid to get the facts on what drug(s) the state will use and from where. Pennsylvania has not executed an inmate since 1999.