(written from a Production point of view)
George E. Allen is an actor who was credited as "Engineer #1" in both the Star Trek: The Original Series episode "The Devil in the Dark" and the Star Trek Encyclopedia (4th ed., vol. 2, p. 540). It is unclear which role he performed exactly, as there are no engineers singled out for such a role appearing in the episode or it's script. In all, only one engineer from the Enterprise appeared in the episode, Scotty's assistant, while, according to the script, the miners from the search party were at one point described as "engineers".
Allen's resume includes films such as The Amazing Exploids of the Clutching Hand (1936), Mysterious Doctor Satan (1940), The Adventures of Martin Eden (1942), The Soul of Nigger Charley (1973, with Fred Williamson, Bob Minor, Tony Brubaker, and Eddie Hice), and Livin' Large! (1991, with Randal Patrick), and guest appearance in television series such as In the Heat of the Night (1989, with Tony Brubaker).