An the fire retardant doesn't? A small amount of salt water wont do any lasting damage.
Five years ago ago I sat and watched as the fire front ran along the overgrown roadside vegetation. It was a long time before the paddocks burned. This was also the case in the Wangary fires a decade earlier when the fire ran at upto 60km/hr. I South Australian CFS stats show that about 50% of fires start on roadsides. Thus it follows that many fires could be prevented by simply management of the roadsides. It used to happen but the we had a green revolution.
But with a month of media beating up the drought, fires, first in the US then on the east coast, the climate extinction people, 11,000 scientists (of which only about 240 hold qualifications in anything remotely climate related) saying we are all doomed it is little wonder the crazies are out in force lighting fires.
End of this rant