More than 200 people fell ill on Wednesday at a pharmaceutical plant located in northern China, after an ammonia gas leak, the state media reported.
The leak occurred when a truck carrying 30 tonnes of liquid ammonia was unloading at the factory located in China's Inner Mongolia Autonomous Region.
According to investigations, the leak was caused by workers failing to operate the equipment properly and old pipes on the truck.
Twenty-one people were hospitalised while 181 others were kept under observation, Xinhua news agency reported. However, no casualty was reported due to the leak.
Meanwhile, authorities were testing the city's water supply for potential ammonia contamination.