Artillery

M825A1 155 mm White-Phosphorus Smoke Projectile

Also known as
  • M825
  • M825A1
  • M825A1 WP
  • M825 white phosphorus
  • M825A1 white phosphorus
  • 155 mm M825A1
  • DODIC D505

The M825A1 is a U.S. 155 mm separate-loading, base-ejection white-phosphorus smoke projectile introduced in March 1985 for screening and marking. Army material describes its 116 felt-wedge payload and 5-15 minute smoke-screen effect, while Human Rights Watch, Amnesty International, and Thai PBS Verify document M825/M825A1-family combat use from Gaza to the Thailand-Cambodia border.

M825A1 155 mm White-Phosphorus Smoke Projectile, 155 mm white-phosphorus smoke projectile, Artillery
Image source: Army obscurant projectiles recapitalization

Role in Conflicts

2008 Gaza War
Fire SupportArea Denial
Side
Israel

During Operation Cast Lead in the 2008 Gaza War, Human Rights Watch documented Israeli 155 mm white-phosphorus artillery fire over Gaza and found spent shells, canisters, liners, and felt wedges from M825A1-type rounds in civilian areas.

2025 Thailand-Cambodia Border Conflict
Fire SupportArea Denial
Side
Thailand

During the 2025 Thailand-Cambodia Border Conflict, Thai PBS Verify reported that CMAC identified a 155 mm M825 white-phosphorus smoke projectile in Oddar Meanchey and that the Royal Thai Army said its WP rounds were used under military-targeting rules.

2023 Israel-Hezbollah Conflict
Fire SupportArea Denial
Side
Israel

In the 2023 Israel-Hezbollah Conflict, Amnesty International documented Israeli artillery-fired white-phosphorus smoke rounds in southern Lebanon and verified M825A1 shells lined up for use beside Israeli M109 howitzers near the Lebanon border.

Profile / Specs

Profile

Origin
United States
Type
155 mm white-phosphorus smoke projectile
Service note
Introduced in March 1985
Designed
March 1985
Unit cost
Not publicly documented
Produced
March 1985-present

Specifications

Caliber
155 mm
Projectile type
Separate-loading, base-ejection smoke projectile
Weight
102.6 lb (46.6 kg)
Payload
116 white-phosphorus-impregnated felt wedges
Fill
12.75 lb (5.78 kg) white phosphorus
Range
22.5 km
Smoke Screen
About 10 m high and 125-250 m wide for 5-10 minutes
Compatibility
M109A6 Paladin, M777A2 towed howitzer, and M198 series howitzers
Ballistic lineage
Ballistically similar to the M483A1 projectile
DODIC
D505
Design Notes

Army ammunition material describes the M825A1 as a long-lived 155 mm obscurant round, built to make a smoke screen rather than to burst as a high-explosive projectile.

FeatureSource-backed detail
DesignSeparate-loading, base-ejection white-phosphorus smoke projectile introduced in March 1985.
PayloadContains 116 white-phosphorus-impregnated felt wedges with 12.75 lb / 5.78 kg of white phosphorus.
EffectProduces a smoke screen about 10 m high and 125-250 m wide for 5-10 minutes, depending on weather and conditions.
CompatibilityArmy material ties it to M109A6 Paladin, M777A2, and the M198 series of 155 mm howitzers.
LineageThe portfolio book describes it as ballistically similar to the M483A1 projectile and lists DODIC D505.
Field identificationARES explains the M825/M825A1 family as a 155 mm white-phosphorus smoke projectile and contrasts it with the M150 HC smoke projectile, which can appear similar in field imagery.

Sources: JPEO A&A Portfolio Book 2017; Army obscurant projectiles recapitalization; ARES M825 WP and M150 HC identification.

Documented Firing Platforms

Army ammunition material treats the M825A1 as a 155 mm family projectile, and combat reporting shows it staged beside Israeli M109 guns.

Firing weaponWeapon typeFiring evidence
M109A6 Paladin, 155 mm tracked self-propelled howitzer, ArtilleryM109A6 Paladin155 mm tracked howitzer

Amnesty International verified M825A1 shells fielded by Israeli forces next to M109 howitzers near Sderot during the 2023 Israel-Hamas War.

Sources: Amnesty 2023 Israel-Hamas War white phosphorus report

M777, 155 mm towed howitzer, ArtilleryM777155 mm towed howitzer

The Army portfolio book lists the M825A1 as compatible with the Lightweight M777A2 towed howitzer.

Sources: JPEO A&A Portfolio Book 2017

M198 155 mm howitzer, 155 mm towed howitzer, ArtilleryM198 155 mm howitzer155 mm towed howitzer

The same Army portfolio book lists the M198 series among the 155 mm howitzers tied to the M825A1 round.

Sources: JPEO A&A Portfolio Book 2017

Why the platform list matters

The Army book presents the M825A1 as a broad 155 mm obscurant round rather than a niche one-gun load, which is why it shows up across older and newer U.S. howitzer families.

Sources: JPEO A&A Portfolio Book 2017

Timeline

M825A1 155 mm White-Phosphorus Smoke Projectile Key Events

  1. Army portfolio dates the round to March 1985

    The Army ammunition portfolio lists the M825A1 as a 155 mm white-phosphorus smoke projectile with an MR date of March 1985.

    Sources: JPEO A&A Portfolio Book 2017

  2. Human Rights Watch publishes Gaza investigation

    Human Rights Watch's Operation Cast Lead report documented Israeli 155 mm white-phosphorus artillery fire in Gaza and identified M825A1-type remnants in civilian areas.

    Sources: HRW Rain of Fire Gaza white phosphorus report

  3. ECBC reports first successful safety tests

    Army reporting says ECBC achieved first successful safety tests in July 2011 as part of the obscurant-projectile recapitalization effort.

    Sources: Army obscurant projectiles recapitalization

  4. Obscurant projectiles return to inventories

    The Army says ECBC reintroduced 54,000 obscurant projectiles to Army and Marine Corps inventories, with roughly 30,000 returning to Army stocks.

    Sources: Army obscurant projectiles recapitalization

  5. Human Rights Watch verifies Gaza and Lebanon airbursts

    Human Rights Watch verified October 2023 video evidence of artillery-fired white phosphorus over Gaza City port and near the Israel-Lebanon border.

    Sources: HRW 2023 Gaza Lebanon white phosphorus report

  6. Amnesty identifies M825 and M825A1 shells near Gaza

    Amnesty's Evidence Lab identified pale-green M825 and M825A1 shells photographed near Sderot beside Israeli M109 howitzers.

    Sources: Amnesty 2023 Israel-Hamas War white phosphorus report

  7. Amnesty documents Israeli border use

    Amnesty International published evidence of Israeli white-phosphorus shelling in southern Lebanon and showed M825A1-marked shells staged beside M109 howitzers near the border.

    Sources: Amnesty 2023 Israel-Hezbollah Conflict white phosphorus report

  8. Thai PBS Verify reports Thai border use

    Thai PBS Verify said the Royal Thai Army used white-phosphorus rounds against military targets during the Thailand-Cambodia border fighting and reported a 155 mm M825 shell in Oddar Meanchey.

    Sources: Thai PBS Verify: 155 mm M825 white phosphorus claim

Media

M825A1 155 mm White-Phosphorus Smoke Projectile Images

M825A1 155 mm White-Phosphorus Smoke Projectile, 155 mm white-phosphorus smoke projectile, Artillery - view 1
Source: Army obscurant projectiles recapitalization
M825A1 155 mm White-Phosphorus Smoke Projectile, 155 mm white-phosphorus smoke projectile, Artillery - view 2
Source: Wikimedia Commons White phosphorus in Gaza in 2009
M825A1 155 mm White-Phosphorus Smoke Projectile, 155 mm white-phosphorus smoke projectile, Artillery - view 3
Source: Wikimedia Commons Fallujah White Phosphorus
Related Weapon Systems
M150 155 mm hexachloroethane smoke projectile, 155 mm HC smoke projectile, ArtilleryArtilleryM150 155 mm hexachloroethane smoke projectile155 mm HC smoke projectileThe M150 is an Israeli 155 mm hexachloroethane smoke projectile from Elbit Systems, built for screening, obscuration, and spotting without white phosphorus. Elbit's product sheet lists five HC smoke canisters, about three minutes of effect, and a NATO NSN, while ARES traces the design to the M483A1 carrier projectile and compares it with M825-series white-phosphorus smoke rounds. Open-source investigations identify M150 rounds in Gaza during the May 2021 escalation and the 2023 Israel-Hamas War.
155 mm artillery round, 155 mm artillery ammunition family, MunitionsMunitions155 mm artillery round155 mm artillery ammunition familyThe 155 mm artillery round is a family-level label for complete 155 mm howitzer shots rather than one projectile model. U.S. Army sources define a complete shot as fuze, primer, projectile, and propelling charge, while manufacturer and conflict records show high-explosive, extended-range, inert, precision-guided, smoke, illumination, cluster, white-phosphorus, and charge-system variants across NATO and NATO-compatible artillery use.

Sources

JPEO A&A Portfolio Book 2017Publisher: U.S. Army | Note: Supports the M825A1 system description, March 1985 introduction, 155 mm smoke-screen role, performance characteristics, DODIC D505, and Pine Bluff Arsenal / General Dynamics-Scranton AAP production context. | Accessed: 2026-06-20Army obscurant projectiles recapitalizationPublisher: The United States Army | Note: Supports the M825A1 smoke-screen purpose, July 2011 safety-test milestone, and Army/Marine Corps inventory recapitalization context. | Accessed: 2026-07-01ARES M825 WP and M150 HC identificationPublisher: Armament Research Services | Note: Supports the M825A1/M825-series technical description, smoke role, and detailed technical specifications. | Accessed: 2026-07-01Amnesty 2023 Israel-Hamas War white phosphorus reportPublisher: Amnesty International | Note: 2023 Israel-Hamas War: Amnesty International's Evidence Lab identified M825 and M825A1 white-phosphorus shells photographed near Sderot beside Israeli M109 howitzers. | Accessed: 2026-07-01HRW Rain of Fire Gaza white phosphorus reportPublisher: Human Rights Watch | Note: 2008 Gaza War: Human Rights Watch documented Israeli 155 mm white-phosphorus artillery fire during Operation Cast Lead and identified M825A1-type remnants in civilian areas of Gaza. | Accessed: 2026-07-01HRW 2023 Gaza Lebanon white phosphorus reportPublisher: Human Rights Watch | Note: 2023 Israel-Hamas War and 2023 Israel-Hezbollah Conflict: Human Rights Watch verified October 2023 airbursts of artillery-fired 155 mm white phosphorus over Gaza City port and near the Israel-Lebanon border. | Accessed: 2026-07-01Thai PBS Verify: 155 mm M825 white phosphorus claimPublisher: Thai PBS Verify | Note: 2025 Thailand-Cambodia Border Conflict: Thai PBS Verify reported CMAC's claim that a 155 mm M825 white-phosphorus shell was fired by the Thai military into the conflict zone and cited the Royal Thai Army statement that WP rounds were used under military-targeting rules. | Accessed: 2026-06-22Amnesty 2023 Israel-Hezbollah Conflict white phosphorus reportPublisher: Amnesty International | Note: 2023 Israel-Hezbollah Conflict: Amnesty International documented white-phosphorus artillery shells used by Israeli forces in southern Lebanon and verified M825A1 shells fielded near the Lebanon border. | Accessed: 2026-07-01Wikimedia Commons White phosphorus in Gaza in 2009Publisher: Wikimedia Commons | Note: Image licensing and provenance page for White phosphorus in Gaza in 2009.jpg; CC BY 3.0 from the Al Jazeera Creative Commons Repository. | Accessed: 2026-06-20Wikimedia Commons Fallujah White PhosphorusPublisher: Wikimedia Commons | Note: Image licensing and provenance page for Fallujah White Phosphorus.jpg; CC BY-SA 4.0 self-published work. | Accessed: 2026-06-20