We had an incident in a nearby town on the Big Island some years ago, before the practice was stopped.
'Waste matter', basically, guts, other bits and 'liquid', would be transported carefully in open wagons to a disposal facility. The smell was a constant cause of discomfort and there were regular complaints. There were also leakage issues and the odd 'splash' from the open tanks.
One day, a driver was proceeding, with his usual care, through the main street of the town, when a woman in a hurry quite legitimately attempted to use a zebra crossing whilst pushing a pram. The driver had no option but to brake heavily, causing a tsunami to surge forwards, over the cab and about thirty yards down the road.
People were literally covered in it, the driver was trapped in his cab and the state of their front steps seemed of little interest to people with the 'material' in their shops...