An ejection system part like this one containing about 0.16 ounces of TNT went missing from a Marine Corps AH-1Z Viper attack helicopter, Thursday, March 16, 2023. (Okinawa Defense Bureau)

CAMP FOSTER, Okinawa — The Marine Corps says it is investigating a pair of unrelated incidents in which a part containing a small amount of explosive went missing from an attack helicopter and a gate guard inadvertently fired his pistol while on duty.

A device containing about 0.16 ounces of TNT went missing from an AH-1Z Viper attack helicopter Thursday, a spokeswoman for the 1st Marine Aircraft Wing told Stars and Stripes by email Friday. The missing device, an ejection system part, was reported during a post-flight inspection, according to Capt. Tess LaBossiere.

The Viper returned to Marine Corps Air Station Futenma shortly before noon Thursday from a flight off Okinawa’s southern coast, she said. The device measures 1.47 by 1.15 inches and weighs less than 1/10th of one pound.

Neither of the two-person crew saw the part fall from the aircraft, LaBossiere said. The Viper’s flight path took it mostly over water.

The device presents no risk of detonating, and if found should be reported to the Okinawa Defense Bureau, according to a statement on the bureau’s website.

“1st MAW takes all aviation related events seriously and is conducting a thorough assessment of the incident,” LaBossiere said.

Separately, Marine Corps Installations Pacific is investigating after a Japanese guard at Camp Foster inadvertently fired his weapon Feb. 14 while on duty at No. 1 Gate.

No injuries or damage resulted when the guard accidentally fired his sidearm in front of the headquarters for the installation command and Camp Butler, Yoshii Higa, a spokesman for the All Japan Garrison Forces Labor Union, said by phone Friday.

The guard said he did not pull the trigger, according to Higa, who said he did not know where the round struck.

The union has been calling for the abolition of armed guards due to safety concerns, Higa said.