OKLAHOMA CITY (AP) — A federal judge in Oklahoma on Tuesday gave the state one month to provide more details on how it plans to train prison workers to carry out lethal injections.

Federal Judge Stephen Friot issued the ruling in a case in which Oklahoma death row inmates are challenging the state’s lethal injection protocols. Friot gave the state until June 5 to provide information and documents on how it’s training members of the execution team.

“It is no secret that inadequate training is the significant factor as to why there were problems in Oklahoma’s past executions,” said Dale Baich, one of the attorneys representing death row prisoners.

Although Oklahoma had considered executing inmates using nitrogen gas, Attorney General Mike Hunter announced in February the state had secured a supply of lethal injection drugs and was ready to resume executions after a five-year delay.

Oklahoma once had one of the busiest death chambers in the nation, but executions were put on hold following a botched lethal injection in 2014 that left an inmate writhing on the gurney and drug mix-ups in 2015 in which the wrong lethal drugs were delivered. One inmate was executed with an unapproved drug and a second inmate was just moments away from being led to the death chamber before prison officials realized the same wrong drug had been delivered for his execution.