Live 25mm M792 HEI-T Round Recovered at Palm Springs Airport — EOD Conducts Blow-in-Place Disposal
Media reports framed this as a Marine “carrying a bomb” through airport security — but the WOME assessment reveals a corroded 25×137mm High Explosive Incendiary cartridge with an indeterminate M758 fuze state, where the real hazard was not the individual’s intent but the degraded condition of a round that had spent approximately twelve months exposed to environmental weathering.
Technical Summary
On 30 March 2026 at approximately 12:05 PDT, Transportation Security Administration (TSA) personnel at Palm Springs International Airport, California, identified a live 25mm explosive round during routine X-ray screening of checked luggage. The Riverside County Explosive Ordnance Disposal (EOD) Unit responded, confirmed the round as live via X-ray examination, and subsequently transported the item to a remote desert location for Blow-in-Place (BIP) disposal through controlled high-order detonation.
The round is assessed as an M792 High Explosive Incendiary with Tracer (HEI-T) cartridge, a 25×137mm fixed-type, percussion-primed round designed for the M242 Bushmaster chain gun. The M792 contains approximately 32 grams of a High Explosive Incendiary (HEI) composition and is fitted with an M758 point-detonating (PD) fuze with self-destruct (SD) function. The complete cartridge has an all-up mass of approximately 500 grams.
The individual, identified as a U.S. Marine, stated he had recovered the round from a field approximately twelve months prior and retained it in the belief it was inert. The round was described as extensively corroded with original identifying markings no longer legible. The Palm Springs Police Department indicated the case would be referred to the Riverside County District Attorney’s Office for potential criminal charges. The Marine may also face Uniform Code of Military Justice (UCMJ) administrative action and TSA civil penalties.
Analysis of Effects
Ordnance Identification and Hazard Classification
The M792 HEI-T is a one-piece steel-bodied projectile with a hollow cavity containing the HEI fill, crimped to a steel cartridge case. Standard identification markings comprise a yellow projectile body with a red band, indicating high-explosive content with incendiary properties. The absence of legible markings on the recovered item is consistent with extended environmental exposure and corrosion.
In its standard storage and transport configuration, the M792 is classified as HD 1.2 (projection hazard, no mass explosion hazard) under UN classification. However, the degraded condition of the recovered round introduces significant uncertainty regarding the fuze state. Corrosion of the M758 PD fuze mechanism may have compromised the arming and safety mechanism, potentially placing the fuze in an indeterminate state between safe and armed.
M792 25mm HEI-T — Technical Specifications
Calibre: 25×137mm NATO
All-Up Mass: ~500 g (complete cartridge)
HEI Fill: ~32 g HEI composition
Fuze: M758 Point Detonating with Self-Destruct (PD/SD)
Hazard Division: HD 1.2 (standard); indeterminate when degraded
Platforms: M242 Bushmaster (Bradley IFV, LAV-25, Stryker ICV), KBA B02, GAU-12/U
Maximum Range: 6,800 m; Maximum Effective Range: 3,000 m
Muzzle Velocity: ~1,100 m/s
EOD Response Assessment
The Riverside County EOD decision to conduct BIP disposal at a remote location is consistent with standard Render Safe Procedure (RSP) doctrine for ordnance in an unknown or degraded condition. When fuze state cannot be determined — particularly where corrosion has potentially compromised safety mechanisms — remote disposal via controlled high-order detonation represents the As Low As Reasonably Practicable (ALARP) approach. Attempting manual disassembly or fuze removal on a corroded PD fuze would introduce unacceptable risk of inadvertent initiation.
Personnel and Safety Considerations
This incident illustrates a recurring pattern in which military personnel or civilians recover what they assess as inert ordnance from training areas. The M792’s relatively small physical size (25mm calibre) may contribute to a perception that the item is harmless. However, the 32 g HEI fill, while producing a comparatively small lethal radius (LR) of approximately 3–5 metres, generates fragmentation (natural, from the steel body) with a Fragment Dangerous Distance (FDD) assessed at approximately 100–150 metres for an unconfined detonation.
For EOD and AT personnel responding to similar recoveries, the corroded condition and absent markings mandate treatment as a worst-case scenario. Specific considerations include potential sensitisation of the explosive fill through moisture ingress, corrosion-induced changes to fuze detent spring tension, and possible crystallisation of the primer composition.
Data Gaps
DATA GAP: Fuze state — Whether the M758 PD fuze was in the armed, safe, or an intermediate condition was not determined prior to BIP disposal. This is standard practice — condition assessment of corroded fuzes carries unacceptable handling risk.
DATA GAP: Explosive fill condition — Twelve months of unprotected environmental exposure may have degraded the HEI composition through moisture ingress. Degraded HEI fills can exhibit altered sensitivity characteristics.
DATA GAP: Recovery location — The specific training area or range from which the round was originally recovered has not been disclosed. This information would be relevant for assessing whether additional Unexploded Ordnance (UXO) may be present at that location.
Authoritative References & Evidential Record
- 1. Palm Springs Today — “Marine Arrested at Palm Springs Airport with Live Explosive Round in Luggage,” 31 March 2026. [Link] [C/2]
Primary source for incident details, EOD response, and Marine’s statement. - 2. GlobalSecurity.org — “M792, High Explosive Incendiary with Tracer (HEI-T).” [Link] [C/1]
Technical specifications reference for the M792 cartridge, HEI fill mass, and fuze designation. - 3. Northrop Grumman — 25×137mm Suite of Ammunition product brochure. [Link] [A/1]
Manufacturer data confirming M792 specifications and platform compatibility.
Corrections & updates welcome. If you hold open-source data that refines or corrects any parameter in this article, please contact [email protected] citing the specific claim and your source. Verified corrections will be incorporated and credited in the revision history.