1.) What caused the toxic waste to begin being pushed to the surface?

In the winter of 1977 when the snow began to thaw, the water runoff sank under the canal and made the chemicals to be pushed above the surface.

2.) What are some of the health hazards associated with the chemicals dumped there?

Many of the chemicals dumped into the canal are known to cause cancer.

3.) Besides humans how are other parts of the ecosystem affected by this?

The chemicals rushed into nearby creeks and contaminated numerous animals habitats, killing many animals.