Question

what did humans do with hazardous waste in the past?
dump it into oceans, rivers, or landfills
recycle most of it for reuse in factories
use it to build houses and buildings

Explanation:

In the past, environmental awareness and proper waste - management techniques were less developed. Dumping into natural water bodies (oceans, rivers) and landfills was a common, though harmful, practice. Recycling hazardous waste on a large scale for factory reuse was not typical due to technological and awareness limitations. Using hazardous waste for building houses and buildings is extremely dangerous and not a historical common practice.

Answer:

dump it into oceans, rivers, or landfills