A test conducted early Thursday showed the water was not contaminated. Results of water quality tests conducted Friday are not yet available.
The incident has revived memories of the contamination of the Songhua River in 2005 after an explosion at a petrochemical plant in Jilin Province left 3.8 million people in Harbin, provincial capital of Heilongjiang, without drinking water for four days.
The 1,900-km long Songhua River is a major drinking water source for tens of millions of people in Jilin and Heilongjiang.