Zane Gbangbola died in 2014 after his home, next to the land, was flooded.
His parents have always maintained his death was due to toxic materials buried at the site.
But an inquest ruled that it was accidental, due to carbon monoxide poisoning from a petrol pump used to divert the flood water away.
Zane’s mum Nicole says it’s taken a long time to get to this point.