An execution chamber in Ohio. (Caroline Groussain/AFP/Getty Images)

Ohio announced this week that it will no longer execute inmates with lethal injection drugs that were involved in two bungled executions last year, a change that will delay at least one execution and possibly others scheduled for this year.

The state’s Department of Rehabilitation and Correction said Thursday that it will no longer use a combination of the drugs midazolam and hydromorphone to carry out executions. This announcement comes nearly a year after Ohio became the first state to execute an inmate with this particular drug combination, an execution that lasted nearly 25 minutes and prompted a lawsuit.

The change comes amid an ongoing drug shortage that was the reason Ohio used this drug combination in the first place, a shortage that has caused states planning to execute inmates to scramble to find the necessary drugs or consider alternative methods of execution.

Going forward, Ohio will only use the drugs thiopental sodium and pentobarbital for its executions, Gary Mohr, director of the Ohio Department of Rehabilitation and Correction, informed District Judge Gregory Frost.

Because it will take time for Ohio to get the drugs, the execution of Ronald R. Phillips, currently scheduled for Feb. 11, will be postponed, the state said. There are also other executions scheduled to occur over the coming months, with the next three lethal injections scheduled for March, May and July, and it is possible some of these will also be rescheduled.

Ohio’s new execution protocol, which went into effect Friday, states that prison authorities should figure out whether there are enough drugs about two weeks before any execution date. If not, corrections officials will notify the office of the governor and the execution could be pushed back to a later date.

Finding the drugs may be difficult, something that has been a recurring problem for death penalty states recently. Lethal injection is the primary method of execution in the United States, but European companies and officials, objecting to capital punishment, have protested the use of drugs supplied by European companies in American executions. This meant that the fairly typical three-drug combination (involving an anesthetic, a paralytic drug and a drug that stopped the heart) used until 2010 has effectively been replaced by experimentation, according to death penalty experts. Four different states (including Ohio) carrying out the first four executions of 2014 used four different drug combinations.

Ohio had run out of pentobarbital, which is why the state used midazolam and hydromorphone to execute Dennis McGuire in January 2014. McGuire, who admitted to raping and murdering a pregnant newlywed named Joy Stewart, choked and gasped before he died. A state investigation later said it found no evidence that McGuire “experienced any pain, distress or anxiety,” while McGuire’s family has filed a lawsuit against state prison officials and others.

Similarly, Arizona was unable to find pentobarbital, so it turned to the same two-drug combination Ohio had used for an execution last summer. Joseph R. Wood, who was sentenced to death for shooting and killing his ex-girlfriend and her father, gasped and snorted during his execution in July, which lasted for nearly two hours, witnesses said. State officials later said that Wood was given 15 doses of each of the two drugs, far exceeding the amount laid out in the state’s official drug protocol.

Midazolam, one of the two drugs used in Ohio and Arizona, was also utilized in Oklahoma’s botched execution of Clayton Lockett in May 2014. Oklahoma did not use the same two-drug combination as Ohio and Arizona, but it was using midazolam for the first time as part of a three-drug combination it had not previously utilized.

Lockett violently reacted to his execution, kicking his foot and grimacing and clenching his teeth. The execution was called off when problems with the IV were discovered, and he was declared dead a short time later. A state investigation later said the execution’s problems stemmed from issues with placing the IV, which meant that the drugs were not properly administered.

These problematic lethal injections drew attention and scrutiny, a rarity since most executions occur hidden away from the public eye and draw little notice. They drew calls from death penalty opponents to abolish capital punishment, but public opinion on the death penalty was largely unchanged after these episodes. Meanwhile, after the Arizona execution, states that execute the most inmates said they did not plan any changes. At the time, an Ohio official said that the state was always evaluating its policies, but could not comment further due to the lawsuit from McGuire’s family.

The ongoing drug shortage is why states have discussed a return to methods like the electric chair, gas chamber or firing squad. Tennessee last year made the electric chair its default method of execution if a lethal injection cannot take place, making it the first state to change its execution protocols since the drug shortage began. These types of things often make headlines, but they may obscure a more notable trend occurring nationwide: The death penalty is on the decline. Last year, fewer states carried out executions, fewer inmates were executed and fewer death sentences were handed down.

Related: Everything you need to know about executions in the United States.