Rapid tests on water samples collected on Friday found the water of three rivers inside the park was polluted by volatile organic compounds - chloroform, methylene chloride, dichloroethane and toluene. But no volatile organic compounds were detected in the waters of the three rivers outside the park.

The polluted water bodies of the three rivers had been cordoned off and so far no pollution was detected in waters outside of the park, according to rescue headquarters.

The Ministry of Ecology and Environment also required special attention for possible rainfall and its impact on handling the aftermath of the blast.

Wei Zheng, a worker with the environmental monitoring station of Funing county, who was sent to Xiangshui county for assistance, said that he got water samples from inside the park and the nearby Guanhe River every three hours for analysis.

"We analyze the chemical remains in the water, including aniline, nitrobenzene and VOC. Environmental protection workers have established eight water monitoring stations inside and near the chemical park," Wei said.