Cambodian soldiers and police are reporting severe breathing difficulties, describing symptoms of suffocation and poisoning following attacks that Cambodian authorities allege involve the use of "toxic smoke" or "toxic gas" by Thai military aircraft. In official statements and press briefings, the Cambodian Ministry of National Defense has repeatedly asserted that Thai forces have used these chemical substances, calling the tactic a clear violation of international law.
From hospital beds in Banteay Meanchey province, affected personnel provided consistent descriptions of the attacks and their immediate effects. Soldier Kun Yong recounted pulling back from his position after trouble breathing from a Thai aircraft sortie, stating, "It's like I was suffocating". Other soldiers and police described Thai aircraft dropping what they called "poisonous water" or experiencing "poisonous smoke" at their bases, leading to symptoms of dizziness, vomiting, and sudden bodily weakness.
Local doctors confirmed treating numerous patients with these symptoms. Dr. Bong Bunnarith reported receiving around 20 soldiers last week suffering from dizziness, vomiting, and difficulty breathing, while Dr. Nak Vanny treated another twenty soldiers on a single Saturday with similar conditions.
These recent military claims are supported by an independent rapid assessment conducted in early September by an alliance of eight Cambodian civil society and environmental organizations . After interviewing soldiers and villagers in border areas, the coalition found "strong indications" that toxic chemical substances were used in the conflict, posing serious ongoing risks to human health and the environment.
The assessment documented consistent reports of hazardous smoke dispersed by aircraft and drones, with victims displaying symptoms like difficulty breathing, dry throat, weakness, headaches, and signs of potential lung damage. Furthermore, villagers reported mass deaths of livestock and poultry, crops turning grey or red, and health issues from using stored rainwater, raising grave concerns about the contamination of local water sources.
The current allegations echo previous accusations from clashes in July 2025, when Cambodia accused Thailand of using white phosphorus munitions . While not classified as a chemical weapon under international conventions, white phosphorus fumes are harmful to the eyes and respiratory tract . Cambodia has not specified if it blames white phosphorus for the latest injuries .
Thai authorities have issued blanket denials. Air Marshal Jackkrit Thammavichai, a spokesman for the Thai Air Force, told Reuters that the air force has never used chemical weapons, dismissing the reports as "fake news" aimed at discrediting its operations. "If it were chemical weapons, they wouldn't be experiencing difficulties breathing, they would have died," he stated. This ongoing dispute occurs amidst fierce fighting that has killed dozens and displaced over half a million people, with Thailand demanding that Cambodia must be the first to announce a ceasefire.
The Cambodian civil society alliance has framed the alleged use of toxic substances as a potential breach of multiple international agreements, including the Geneva Protocol, the Chemical Weapons Convention (CWC), and international humanitarian law. They have called for urgent action from the UN, ASEAN, and the international community to halt the attacks, ensure civilian protection, and conduct independent technical studies to identify the substances and establish accountability .
The Cambodian government, for its part, has accused Thailand of waging a "psychological war" alongside physical attacks, aiming to discourage Cambodian forces and citizens. As the conflict enters its tenth day, with displacement figures surpassing 420,000 people, these grave allegations add a dangerous new dimension to one of Southeast Asia's most intense border wars in decades.