Or a simple truck spraying oil on dirt roads to eliminate dust.
This is an
image of the Route 66 State Park in Missouri. If you look close, you'll notice the trees seem to grow in lanes. That's because the park used to be a small city called Times Beach. The lanes are the old dirt roads that had to be oiled to keep the dust down.
The person hired to do the oiling was a guy named Russell Bliss. Aside from hauling waste and oiling roads, he also subcontracted with a company called IPC to dispose of some of their waste. ICP was being paid $3,000 a load to haul toxic waste from a chemical company called Northeastern Pharmaceutical and Chemical Company and they would then turn around and pay Bliss $100 a load to dispose of it.
He disposed of it by mixing it with the oil he used to spray roads, stables, etc for miscellaneous customers, including the city of Times Beach. He dumped so much dioxin on the city roads that the federal government bought up the entire town, moved the residents, and then dug up a layer of topsoil, roads, etc to be incinerated.
Now the spot where the town used to be is the
Route 66 State Park.
It doesn't take a terrorist - just some ignorant old guy that never finished high school that has no idea of what he's disposing of (of course, the fact that he mixed it with engine oil to dispose of it suggests he knew more than he ever admitted).