It must have went airborne for quite as distance, there is Black Liquor smeared all over the Town of Jay.....
Trucks got hosed down by the local FD, some better than others from what I'm hearing...quite a few spotted Aluminum rims as a result...
The paper mill smell is predominately from the Black Liquor. That's what rained down on the trucks mixed with wood fibers. I have hauled Black Liquor in Chemical Tankers as it is used as fuel in Recovery Boilers at the mills. Sometimes one mill cannot burn all the Black Liquor on site so it is trucked to other paper mills for use in their Recovery Boilers.
So you haul Black Liquor one way and then Green Liquor back. That is what is left after being run through the boilers.
The three stages linked below starting with the caustic White Liquor...
https://en.wikipedia.org/wiki/White_liquor
Then after the pulping process..
https://en.wikipedia.org/wiki/Black_liquor
Then after being used as fuel for the Recovery Boiler
https://en.wikipedia.org/wiki/Green_liquor
Recovery Boilers need to be inspected regularly as those are capable of flattening a city block if there is an issue...
First rule of Caustics is "You can put Caustic on water but you cannot put water on Caustic....so a water leak in the boiler itself can result in an earth shattering explosion....
When hauling Caustic and the customer wants less strength you always put the water in the tanker first and then went to the Caustic loading station.
Some of the guys blew up a 5 gallon pail one evening testing the water on Caustic theorem......after that they were believers for sure....sure as hell didn't want to see it happen in a 5,000 gallon tanker...