Arkansas' prison spokesman said Friday that he is "unaware of any efforts" to find a new supply of an execution drug that expired at the start of the new year.

The Department of Correction has not restocked its expired batch of potassium chloride, spokesman Solomon Graves said, adding that the state's remaining supply of execution drugs remains unchanged. Graves declined to comment further.

In September 2015, Gov. Asa Hutchinson set execution dates for eight men on death row. However, their executions were placed on hold due to a legal challenge, lodged by the eight men and another inmate, of the state's three-drug "cocktail" method of execution, which is pending a review by the U.S. Supreme Court.

Potassium chloride is the third and final drug used in executions; it causes cardiac arrest and death. The first drug, midazolam, is an anesthetic and is followed by vecuronium bromide, a muscle relaxer.

In emails sent last fall, Graves detailed the expected expiration dates of the state's supply of execution drugs: potassium chloride this month, followed by midazolam in April and vecuronium bromide in March 2018. The drugs would expire at the end of the month, Graves wrote, "unless otherwise specified."

Graves specified this week that the batch of potassium chloride expired Jan. 1.

Arkansas has not executed an inmate since 2005, due to legal challenges and its difficulty in obtaining execution drugs.

The Legislature passed Act 1096 in 2015, amending the execution statutes to allow for the usage of either a three-drug cocktail or a single dose of barbiturate. If lethal injection is struck down by the courts, the law authorizes executions by electrocution.

Within months of the law's passage, Hutchinson scheduled the series of executions, to begin in the fall of 2015. None were carried out after the Arkansas Supreme Court issued a stay over the prisoners' court challenge.

The state's high court this summer upheld the state execution law, but agreed to continue the stay so that the prisoners could take their case to the U.S. Supreme Court.

The prisoners are asking the U.S. justices to review their previous decision upholding the use of midazolam in Oklahoma executions.

Midazolam has been accused of causing several botched executions in other states, including Oklahoma, with reports of condemned prisoners heaving and gasping before death.

While the deaths of the inmates were on hold this summer, the state's supply of vecuronium bromide expired, but a new batch was acquired less than two weeks later.

Thirty-four men are on death row in Arkansas.

Metro on 01/21/2017