The newspaper explained that the military officials of the Sudanese army tried to hide the supplies after using chlorine bombs against the Rapid Support Forces.
He indicated that video clips, documents, text messages and other materials were reviewed and confirmed the use of chlorine by the Sudanese army in making bombs.
Chlorine bombs instead of clean drinking water
The materials indicate that chemical weapons efforts in Sudan included shipping chlorine intended to provide clean drinking water, hiding warhead production facilities in military bases, testing bombs in remote desert areas, and preparing lists of targets where the poison gas would penetrate enemy defenses.
The collection was provided to The Washington Post by Middle East security officials who said the materials were obtained from sources in Sudan.
The files include documents prepared by Sudanese military officials regarding “dual-action” munitions filled with “asphyxiant gas,” videos showing tests of weapons that produce green and yellow fumes, and reports among Sudanese military officials that army forces have stockpiled up to 290 chemical munitions.
In examining the files, The Washington Post consulted more than 20 Western intelligence officials, chemical weapons inspectors and experts from human rights organizations. All describe the materials as credible evidence of the existence of a chemical weapons program.
“The evidence is disturbing and deeply disturbing,” said Gareth Williams, a former senior official at the Organization for the Prohibition of Chemical Weapons and a current senior fellow at the Royal United Services Institute, Britain’s defense and security think tank.
Williams added that the accumulation of chlorine munitions “cannot be verified by visual evidence alone, but the indications are strongly consistent with the existence of a chemical weapons program.”
According to security officials and experts, chlorine gas munitions – a primitive weapon dating back to World War I trench warfare – are unlikely to change the stalemate in Sudan.
But text messages sent by Sudanese military officers, according to Middle East security officials, indicate that the Sudanese military saw chemical attacks as a way to incite terror and drive enemy forces from entrenched positions.
In one conversation, a person identified as a Sudanese officer points to police barracks, including guard towers under RSF control, and says the compound “must be targeted … all these towers will be covered with gas and any snipers will fall” where army fighters can “neutralize” them.
The letters were sent in December 2024, according to materials provided to The Washington Post, three months after the United States accused Sudan of chlorine gas attacks on the Al-Jil oil refinery and the Ghare military base, north of Khartoum.
There are indications in the files that Sudan has used chlorine bombs on other occasions.
A text conversation in late 2024 shows a Sudanese army officer reporting that hundreds of chlorine bombs had been collected and stored at Marow Air Base, the main facility of the Sudanese air force, and that 106 bombs had been used.
Another message, allegedly sent to a Sudanese army officer involved in the airstrikes, includes a video of an alleged war victim with charred skin. The message read: “Your food.”
Middle East security officials who provided the documents to The Washington Post identified the sender of the messages as Tariq Madani, whom officials described as an officer in the Sudanese armed forces and the chief architect of Sudan’s chemical weapons program.
According to Middle East security officials, Madani appears repeatedly in the materials, including sending photos of alleged bomb assembly facilities, commenting on warhead specifications and exchanging messages about the program with Sudanese officials, including Burhan.
Middle Eastern security officials have provided a cellphone number linked to messages and voice memos attributed to Madan.
The Sudanese military appears to have relied on scrap components, chlorine shipments and a primitive manufacturing process to assemble its alleged arsenal, according to the materials.
The collection includes photographs and video clips showing dozens of improvised bombs stacked in warehouse-like structures.
Several photos show a set of cylinders, such as those commonly used in home barbecues, tanks whose primary use is to store liquefied gas. Welders then fit them with a pointed nose, spring-loaded firing pins and aerodynamic fins designed to ensure that the bombs fall from the nose to the targets.
One of the videos, according to the newspaper, shows a primitive system for filling ammunition with chlorine removed from huge yellow storage cylinders.
The video shows metal tanks connected to a chilled water source with new valves and hoses.
Weapons experts said the system was likely used to cool the cylinders as they were filled with liquefied gas, a process that generates heat.
Other photos show a weapons carrier attached to the cargo floor of an Antonov An-32, a Soviet-designed aircraft used by the Sudanese air force.
Weapons experts said the mechanism appeared to be designed to function as a conveyor belt, allowing the bombs to be loaded and dropped from the plane’s cargo door.
The most interesting images in the files show alleged weapons tests in remote desert locations.
One of the documents describes the specifications of a four-foot-tall “double-thump” bomb, which is missing “15 kilograms of gas” in addition to 20 kilograms of explosives.
The files also indicate that Sudanese army officers were focused on covering their tracks.
The same document includes text in Arabic that reads: “The main purpose of the new design is to hide any evidence of the use of chemicals and to release the gas directly from the tank in an ideal way,” according to a Washington Post translation.
source of chlorine
The materials provide conflicting information about how to obtain chlorine, a chemical vital to eliminating harmful bacteria from water supplies, but when used in a bomb, it burns the skin and enters the lungs, potentially causing respiratory failure.
Documents and letters in the collection indicate that chlorine sources come from India as a water treatment material, while letters, which Middle Eastern officials say were sent by civilians, mention the arrival of 20 large tanks at a border crossing with Egypt and confirm the production of up to 1,100 bombs.
Other messages mention water treatment facilities. The audio, which officials attribute to Ore, refers to “chlorine cylinders used to sterilize and hunt bacteria” at the treatment facility.
The spokeswoman says the cylinders “come through UN health programs or something like that,” adding that “we got some of them from there.”
A spokesman for UNICEF, the UN agency focused on child protection, said it had supplied chlorine gas to the Khartoum State Water Authority from 2023 to 2025 for use at six water treatment plants, including al-Manara, the facility mentioned in the files.
A spokesman said UNICEF is monitoring these shipments and has “no record of diversion or misuse of chlorine supplied by UNICEF to Sudan.”
Spokesman Joe English said: “The chlorine provided by UNICEF has one purpose: to make the water safe to drink. Any other use would be a serious breach of its terms of reference and humanitarian aid delivery principles.”
The United States last year announced new sanctions against Sudan in response to its alleged use of chemical weapons and imposed restrictions on loans, exports and technical assistance to the country.
The State Department said at the time that it had determined that Sudan had “used chemical weapons in violation of international law,” but provided few details about the evidence it used to make that determination.
In a September 2025 letter that Middle Eastern officials said was written by Madani, he tried to assure Burhan that the military base where the weapons were stored had been “cleared of relics and remains,” according to the text messages.
In an attempt to avoid international pressure, al-Burhan publicly announced last May the formation of a Sudanese committee to investigate allegations of chemical weapons use by the Sudanese armed forces.
A document outlining the investigation referred to the involvement of the civilian “because of his expertise” – giving the supposed engineer of the program an alleged role in the investigation. The document is dated July 2025 and bears Al-Burhan’s signature.
Sudan announced the results of that investigation last fall, saying that “based on available evidence and data from field measurements … there is no evidence of chemical or radioactive contamination.”
Tariq Madani, Program Engineer
The documents put the person in charge of the program, Tariq Madan, in contact with al-Burhan. A message also appears stating that the repository has been cleared of antiquities and remains, and a civilian is later included in an official investigation committee into the allegations.
The materials indicate the use of a shipment of chlorine originally intended to purify drinking water, the arrival of 20 tanks at the Egyptian border, and the theoretical capacity to produce 1,100 bombs. It also notes records of cylinder pickups from water treatment facilities.
According to the report, the bombs are relatively primitive and some are designed to combine 15 kg of gas and 20 kg of explosives in an attempt to design them to hide the effects of chemical use.
More than 20 experts and intelligence officials considered the material a strong indicator of the existence of a chemical program, but stressed that definitive proof would require access to facilities and witnesses inside Sudan. Digital evidence experts also found no evidence of forgery in the materials they examined
