The NW Disposal Systems was a pre-War company that specialized in nuclear waste disposal. Their flatbed trucks could be unmistakably identified by their characteristic white paintjob and atom-like logo on the cab doors.
Three of their trucks were transporting nuclear waste throughout the Mojave on October 23, 2077. When the Great War took place, two of them were secured in the Searchlight fire station, while the third continued towards Cottonwood Cove. Two other trucks are found near the Junction 15 railway station and the Powder Ganger camp west.
NW Disposal Systems is only mentioned in Fallout: New Vegas.