China had to dump more chemicals to clean up the toxic river. The cadmium containing slick forced people to cut off tap water. The slick was then flushed into the North River, running to the Guangdong province north to south. The sludge was then enclosed by a dam, where chemicals were dumped to neutralize it.
The chemical benzene was tested to check if the concentration of it were within safety regulations. Luckily it was. Although do we really know for sure that whether it was safe. Only the fishes would be able to tell us.