With capital punishment dominating headlines, PostTV looks at the latest statistics on the death penalty in the United States, and in the 21 other countries that executed inmates in 2013. (Davin Coburn/The Washington Post)

States should use only one drug to carry out death sentences, and it should be a single anesthetic or barbiturate that the U.S. government has approved for executions, according to a new report by a bipartisan panel of criminal justice experts that will be released Wednesday.

The 165-page study by the Constitution Project, a nonpartisan legal research organization, also recommends that states adopt lethal-injection protocols that are transparent, including providing information about the drugs used and the qualifications of the people administering them.

“Without substantial revisions — not only to lethal injection, but across the board — the administration of capital punishment in America is unjust, disproportionate and very likely unconstitutional,” Mark Earley, a member of the Constitution Project’s death-penalty committee, said in a statement. Earley was the Republican attorney general of Virginia from 1998 to 2001, when the state carried out 36 executions.

The report, “Irreversible Error,” does not take a position on the use of the death penalty but instead makes 39 recommendations to courts and policymakers in states that choose to use it, with the goal of preventing errors in the administration of capital punishment.

The findings are being released a week after Oklahoma’s bungled execution of convicted murderer Clayton Lockett, who was given an injection of a three-drug cocktail from undisclosed sources. Lockett struggled on the gurney before dying of an apparent heart attack after 43 minutes. Oklahoma, like some other states, uses unproven drug cocktails; states say they need to conceal the source of the drugs to protect their suppliers from legal action and harassment.

President Obama last week said that the United States continues to have “significant problems,” including racial bias, in the application of the death penalty. Obama asked Attorney General Eric H. Holder Jr. to examine the issue and report to him.

In a statement, former Texas governor Mark White, co-chair of the Constitution Project’s death-penalty committee, said the new report “provides a detailed road map” for the Justice Department to follow. The report was assembled by a panel that included former state attorneys general, governors, judges, police chiefs, corrections directors, victims’ advocates and law enforcement officials.

Problems with lethal injections are only a small part of what troubles the administration of capital punishment in America, said White, a death-penalty supporter who oversaw 19 executions when he was governor.

“From the moment of arrest to the moment of death, the criminal justice system faces vexing challenges in carrying out the ultimate punishment,” White said in the statement.

The report recommends that Congress develop federal standards for accrediting forensic laboratories and that only examiners from labs that meet the accreditation standards be allowed to testify in capital cases. The report also said that forensics labs should operate independently of law enforcement to avoid bias in the processing of evidence.

More than 50 percent of the first 225 erroneous convictions overturned by DNA testing involved invalid or improper forensic science, according to the Innocence Project, an organization that uses DNA testing to exonerate people who were wrongly convicted.

The report recommends procedures and standards of proof that it suggests states should adopt in evaluating a defendant’s claim of intellectual disability.

In 2002, the U.S. Supreme Court held that it is unconstitutional to execute a person with “mental retardation.” But the court largely left the details of implementing the decision to the states. Some states adopted definitions of intellectual disability that are at odds with clinical consensus and demand a burden of proof for establishing intellectual disability that is too stringent, according to the report.

More than 10 years after its initial ruling, the Supreme Court is examining the constitutionality of how some states determine whether or not a defendant is intellectually disabled. The court heard oral arguments in Hall v. Florida in February and is expected to rule before the end of the current term.

“We hope these recommendations will be embraced by officials from both parties in Washington and around the country,” Earley said in his statement. “There’s nothing conservative about executing an innocent person, and leaders who support the death penalty bear the greatest responsibility in ensuring it is administered more fairly.”