A third person is set to be executed by nitrogen gas, Alabama authorized Wednesday, months after becoming the first state to put a person to death with the previously untested method.

The Alabama Supreme Court granted the state attorney general’s request to authorize the execution of Carey Dale Grayson, one of four teenagers convicted in the 1994 killing of Vickie Deblieux in Jefferson County. Alabama Gov. Kay Ivey will set Grayson’s execution date.