USS ESSEX -- One Marine was killed when an MV-22 Osprey from the 15th Marine Expeditionary Unit experienced a hard-landing mishap while conducting training aboard  Marine Corps Training Area – Bellows at approximately 11:40 a.m., Hawaii time. 

Twenty-two Marines were aboard at the time, and all other 21 have been transported to local hospitals for assessment and treatment.

The Marines were conducting routine sustainment training at the time. The 15th MEU departed San Diego May 10 on a seven-month deployment to the Pacific Command and Central Command areas of operation. 

The cause of the incident is under investigation.