These has been a serious incident of poisoning at the Ulaanbaatar Wastewater Treatment Plant, which has led to four deaths and the hospitalization of five others. The tragedy took place at 6.30 pm on Tuesday (16 April). According to one source, the victims were aged between 30 and 35. The five others are being treated in intensive care in the Central Hospital of Mongolian Armed Forces. It appears that their condition has stabilized.

It appears that some highly poisonous component had accumulated in a 50-90 cm layer of sludge, with which the workers had direct contact.