In November, two people were killed and 24 others injured in an explosion at a machinery plant in the northern Chinese province of Jilin.
Authorities said they had also dammed a tributary to the nearby Xinfeng River to prevent any "outflow of sewage from the chemical industrial park".
Meanwhile, classes at the almost 10 schools in the area will be suspended.
The explosion toppled several buildings in the industrial park and caused a huge fire that raged through the night, while rescuers scrambled to find survivors in the wreckage of the plant owned by a company with a chequered past.
Nearby residents - many of them elderly - have started sweeping up glass, and in some cases, seemed to have abandoned their homes entirely. "Why hasn't the government sent us some water?"
While there is a small river next to the site, it is not used as a drinking source, the agency added.
Wan Pingyu, professor of applied chemistry at Beijing University of Chemical Technology, said that the leak of the toxic chemicals might have affected the surrounding people and environment.
The cause of the explosion was under investigation, but an editorial in the China Daily newspaper speculated it was likely to be identified as "a serious accident caused by human negligence". The factory was engaged in producing fertilizer. It has been fined six times in the past three years for air pollution and solid waste management violations, Beijing News reported. Just a year ago, the authorities found 13 types of safety hazards, some of them involving tanks of toxic benzene believed to be the source of the explosion.
This industrial town in Jiangsu province, the country's main producer of agricultural chemicals, is no stranger to accidents. More than 3,000 workers and around 1,000 residents have been relocated to safe places.
At least 47 people were killed when an explosion rocked the industrial zone there on Thursday.
The incident calls to mind what happened on August 12th, 2015 in Tianjin when a massive chemical blast killed 173 people and left behind a colossal crater at ground zero.
On Xi's orders, State Councilor Wang Yong led officials from the State Council, China's Cabinet officials to the explosion site to "guide the rescue and emergency response work and visit the injured people", Xinhua said.