South Dakota has dismissed a criminal charge against a SkyWest Airlines pilot accused of being under the influence of alcohol before a flight at an airport in the state.

Pennington County Chief Deputy State's Attorney Lara Roetzel said Monday that the state filed for dismissal because a blood draw showed no measurable alcohol in his system.

The 39-year-old pilot was arrested Oct. 26 at Rapid City Regional Airport after a security worker noticed he smelled like alcohol and notified authorities. The pilot was arrested before passengers had boarded.

Roetzel says that although a breath test showed a level above the legal limit of 0.04 percent, that level had dissipated by the time his blood was drawn four hours later. Breath test results are not admissible in court.