Why are states like Alabama, which is planning to use nitrogen gas, exploring new execution methods?

By SEAN MURPHY
Associated Press

OKLAHOMA CITY (AP) — An Alabama execution this week would be the first in the nation to use nitrogen gas. It follows a long history of problems with lethal injection since Texas first used the method in 1982. Numerous other states that use lethal injection have encountered various problems. These include difficulty finding usable veins, needles becoming disengaged or problems obtaining or using the lethal chemicals. Alabama, Oklahoma and Mississippi all have authorized the untested use of nitrogen gas to execute prisoners, although none has actually used it.