Schneider said the fire started with a flash explosion as the truck's operator was pumping the trailer's flammable contents into the structure where the three workers were putting in insulation. It's unclear what ignited the fire, though early speculation among fire officials is centering on space heaters.
Schneider said the processing facility was built within the last several years at an old well site. The region in recent years has seen an influx of companies seeking to profit from the pool of oil that lies beneath western North Dakota, northeast Montana and part of Canada.
Custom Carbon Processing on its website said it uses a complex process to convert residual wastes, called slop oil, from the oil producing process that would otherwise be discarded and turns it into pipeline-grade oil the company sells to oil buyers.
According to the website, the company is a wholly owned subsidiary of Green Oasis Environmental Inc. That company lists its headquarters as being in Edmonton, Alberta, and has an office in Gillette, Wyo. Officials at that company did not respond to requests for information from the AP on Sunday.