Kenneth Smith in an undated Alabama corrections photo.
Kenneth Smith, seen here in an undated Alabama corrections photo, is due to be executed with nitrogen gas in January.
  • Alabama is planning to execute a man using nitrogen gas.
  • But the untested execution method may be dangerous.
  • State officials warned the inmate's spiritual advisor that a mishap could put others in danger.

Alabama plans to be the first US state to use nitrogen gas to execute a prisoner.

But the untested method of execution could be dangerous to those nearby, specifically the man's spiritual advisor, who would be in the room when he's killed, according to the exclusive report by NPR.