Technical Summary

The Cambodia Mine Action Centre (CMAC) has reported a milestone in a China-aided landmine and Unexploded Ordnance (UXO) clearance programme running from 2018 to February 2026. Over the eight-year programme, CMAC reports the clearance of over 19,000 hectares (190 square kilometres) of contaminated land and the destruction of more than 105,000 landmines and UXO items. The programme has directly and indirectly benefited over 378,000 families — approximately 1,454,000 people — and delivered Explosive Remnants of War (ERW) risk education to more than 4.6 million Cambodians.

Cambodia remains one of the most heavily mine- and UXO-contaminated nations on earth. The contamination is a legacy of decades of overlapping conflicts: the United States conducted extensive aerial bombardment campaigns between 1965 and 1973, dropping an estimated 2.7 million tonnes of ordnance — more than was dropped on Japan during the entirety of the Second World War. This was followed by the Khmer Rouge era (1975–1979), the Vietnamese invasion and occupation, and a protracted civil war that did not formally conclude until 1998. The cumulative effect is an estimated 4–6 million landmines and millions of additional UXO items scattered across the country, concentrated in the northern and western provinces but present in every region.

The 19,000-hectare clearance figure, while representing substantial operational effort, must be set against the scale of remaining contamination. Cambodia’s Baseline Survey identified approximately 648,000 hectares of confirmed or suspected contaminated land. At the average clearance rate achieved by this programme — approximately 2,375 hectares per year — the remaining contaminated area would require over 260 years of sustained effort at current rates from this single programme alone.

Analysis of Effects

The ordnance types likely encountered across 19,000 hectares of Cambodian terrain span multiple conflicts, multiple origin nations, and multiple threat categories. Anti-personnel mines from Soviet, Chinese, and American production are the most commonly encountered items in Cambodian clearance operations. The PMN (Soviet, 240g TNT fill) and Type 72 (Chinese, 51g TNT fill) are blast mines that degrade unpredictably over decades — the bakelite and plastic casings deteriorate, and the pressure plates may become sensitised or desensitised depending on environmental conditions. The US-origin M14 (29g Tetryl) is a minimum-metal mine that remains extremely difficult to detect with conventional metal detectors.

The cluster submunition contamination is arguably the more technically challenging problem. US forces dropped large quantities of CBU-24, CBU-29, and CBU-58 cluster bomb units across eastern Cambodia, each dispensing hundreds of BLU-26/B bomblets. The BLU-26/B is a baseball-sized fragmentation submunition containing approximately 28 grams of Composition B and 300 steel balls. Published dud rates for these submunitions range from 5% to 30% depending on drop altitude, fuze type, and terrain — meaning that for every cluster bomb unit delivered, dozens of armed submunitions remained on or just below the surface. The BLU-42/66 DRAGONTOOTH is a particularly insidious anti-personnel mine submunition designed to blend into its surroundings, with a flat profile that makes visual detection difficult and a minimal metal signature.

Larger UXO items — including general-purpose bombs from the Mk 80 series and the M117 demolition bomb — present a different risk profile. A single Mk 82 (500 lb class) contains approximately 87 kg of Tritonal or H-6 explosive fill. These items are typically found partially or fully buried and may have armed fuzes in an unknown state. The fuzes fitted to US bombs of this era (M904, M905 nose fuzes; M906 tail fuze) can be in any condition after fifty years in waterlogged Cambodian soil — from completely inert to extremely sensitive due to corrosion and energetic migration.

HD/CG Classification Note

ERW and UXO found in the field cannot be classified per the standard Hazard Division / Compatibility Group framework. HD/CG classification under STANAG 4123 and AASTP-3 applies to ammunition in its designed packaging configuration — not to corroded, armed, or damaged items found in uncontrolled field conditions. Each item found by CMAC clearance teams must be assessed individually for fuze state, energetic condition, casing integrity, and environmental factors before any handling or disposal decision is made.

Personnel and Safety Considerations

CMAC operates under the oversight of the Cambodian Mine Action and Victim Assistance Authority (CamAA) and conducts clearance operations in accordance with International Mine Action Standards (IMAS). Cambodia has one of the most mature national mine action programmes in the world, with CMAC having operated continuously since 1992. The organisation employs manual demining, mechanical clearance (flails and tillers), and mine detection dogs (MDDs) in an integrated approach that is considered best practice within the humanitarian mine action community.

The ERW risk education component — reaching 4.6 million people — is a critical force multiplier. In a country where contamination is so widespread that complete physical clearance will take generations, community awareness of mine and UXO recognition, safe behaviour in contaminated areas, and reporting procedures directly reduces casualty rates. Cambodia has seen a significant reduction in annual mine/ERW casualties from over 4,000 in the mid-1990s to under 100 in recent years, and community education programmes are a major contributor to this reduction alongside physical clearance.

Data Gaps

DATA GAP: Ordnance type breakdown — No breakdown of the 105,000 items by type (mines vs UXO vs submunitions vs aerial bombs) has been published. This prevents assessment of the relative threat composition and estimation of remaining contamination density.

DATA GAP: Specific types and origins — The specific ordnance types and national origins encountered in this programme have not been reported. The types listed in this assessment are based on the known Cambodian contamination profile, not programme-specific reporting.

DATA GAP: Remaining contaminated area — The current estimated remaining contaminated area in Cambodia has not been confirmed against this clearance milestone. Cambodia’s 2009 Baseline Survey identified approximately 648,000 hectares, but subsequent non-technical and technical surveys have both added and released land.

DATA GAP: Annual clearance rate trend — Whether the annual clearance rate (hectares/year) has been increasing or decreasing over the eight-year programme period is not reported. Clearance rates vary significantly depending on terrain type, contamination density, and seasonal access.

DATA GAP: Programme funding and sustainability — The total funding level of the China-aided programme and its sustainability beyond the current phase have not been disclosed. Dependency on a single donor programme creates continuity risk.

DATA GAP: Clearance team casualty rates — Occupational casualty rates among CMAC clearance personnel during the programme have not been reported. This is essential for assessing whether operational safety standards are being maintained as clearance rates increase.

DATA GAP: Disposal methodology — Whether any items required specialist EOD disposal versus routine demolition, and the proportion of in situ destruction versus consolidation for batch demolition, has not been specified.