Alabama is seeking to put a second inmate to death using nitrogen gas, a move that comes a month after the state carried out the first execution using the controversial new method.

Alabama Attorney General Steve Marshall’s office asked the state Supreme Court on Wednesday to set an execution date for Alan Eugene Miller. The state said Miller’s execution would be carried out using nitrogen. Miller, now 59, was convicted of killing three people during a pair of 1999 workplace shootings in suburban Birmingham.

“The State of Alabama is prepared to carry out the execution of Miller’s sentence by means of nitrogen hypoxia,” the attorney general’s office wrote, adding that Miller has been on death row since 2000 and that it is time to carry out his sentence.