Eighteen people were injured in an ammonia leak at an ice plant in southern Thailand.

Factory workers were inspecting the gas storage in the facility when a large metal object reportedly fell and ruptured the ammonia pipes in Pattani province on November 13.

Police Colonel Jeffrey Saimankun, superintendent of the Mueang Pattani Police Station, said the incident was reported at 10 am.

Firefighters and rescue volunteers arrived and doused the area in water to neutralise the vapours before sealing the source of the leak inside the factory.

Authorities said 18 people who suffered dizziness, difficulty breathing, eye irritation, and vomiting, were rushed to the hospital.

Pattani Governor Pateemoh Sadeeyamu later arrived and set up a command centre in the area. She ordered nearby schools and daycare centres to close, and urged local officials to enforce mask wearing.

She said: 'People within the three-mile (five-kilometre) radius of the ice plant should wear layers of face masks or N95 masks.'

She added that the factory has been cordoned off for inspections.

The provincial authority said there were more than 20 ice factories using ammonia in the province, with two or three leaks occurring recently despite regular inspections. Local officials said they will educate residents on how to respond to such leaks.

Ammonia is commonly used as a fertiliser in agriculture to provide nitrogen, an essential nutrient for plant growth. It is also used in industrial applications, such as refrigeration, cleaning products, and the production of chemicals like nitric acid.

Despite its widespread use, ammonia is toxic in high concentrations and can cause severe respiratory irritation, eye damage, or even lung injury if inhaled in large quantities.