ARLINGTON NATIONAL CEMETERY, Va. – A Vietnam veteran, former Army Explosive Ordnance Disposal technician and retired Navy vice admiral made a lasting difference for his nation.

U.S. Navy Vice Adm. John M. Mateczun was honored by U.S. military leaders during his interment ceremony at Arlington National Cemetery, Virginia, on May 9, 2024.

U.S. Army Explosive Ordnance Disposal leaders from the 20th Chemical, Biological, Radiological, Nuclear, Explosives (CBRNE) paid tribute to retired vice admiral and former Army EOD tech.

Mateczun of Edgewood, Maryland, passed away Nov. 7, 2022, at age 76.

Originally from Albuquerque, New Mexico, near Kirtland Air Force Base, Mateczun enlisted in the U.S. Army in 1966 and deployed to Vietnam twice.

During his first deployment in 1967 – 1968, Mateczun served as an Army fire control instrument repairer in the 94th Maintenance Company, 25th Infantry Division, at Cu Chi, Vietnam, and participated in the counteroffensive to Tet offensive in early 1968.

His experience in Vietnam led him to volunteer to serve as an Army Explosive Ordnance Disposal technician.

He served as the EOD team sergeant with the 5th Ordnance Detachment (EOD) on Okinawa, Japan, and deployed to Korat, Thailand, for theater EOD operations.

In September 1969, Mateczun deployed again to Vietnam as EOD team sergeant with the 184th Ordnance Detachment (EOD) at Qui Nhon, where he was awarded a Bronze Star for his heroism during combat.

He cleared numerous booby traps from main supply routes.

Following his honorable discharge from the Army in 1970, Mateczun earned his bachelor’s degree and medical degree from the University of New Mexico and graduated in the same medical school class as his brother in 1978.

After commissioning in the U.S. Navy Reserve, Mateczun completed his residency at the Naval Regional Medical Oakland, California, in Psychiatry. Mateczun later earned a law degree from Georgetown University.

Often responding after traumatic events, Mateczun supported the crews of submarine USS Bonefish (SS 582) following a fire in 1988, the guided missile cruiser USS Vincennes (CG 61) in 1988 after it had mistakenly shot down a commercial Iranian airliner and the battleship USS Iowa (BB 61) after a turret explosion in 1989. He also supported prisoners of war returning from Operation Desert Storm.

Mateczun commanded Naval Hospital Charleston, South Carolina, and Naval Medical Center San Diego.

He was the senior medical officer at the Pentagon on 9/11 and led the medical response effort.

Mateczun later led the major merger between the National Naval Medical Center (NNMC) and the Walter Reed Army Medical Center (WRAMC).

During his 38 years in uniform, Mateczun became one of only two Navy psychiatrists to make three-star admiral.

Col. Gregory J. Hirschey, the deputy commander of the U.S. Army 20th CBRNE Command, and Sgt. Maj. Dustin R. Rolfe, the 20th CBRNE Command Operations Directorate (G3) sergeant major, attended the ceremony on behalf of the nation’s premier CBRNE command, which is home to 75 percent of the active-duty U.S. Army EOD technicians.

Hirschey said all EOD technicians share a common bond forged through confronting and defeating explosive threats.

“Vice Adm. Mateczun wore the same badge that bonds together EOD technicians across the services and throughout our history,” said Hirschey, a native of East Helena, Montana. “He served our nation with great distinction both in Army green and Navy blue and we are proud to recognize his service on behalf of all EOD technicians.”