Honestly? I could call it Lawful Neutral. Dan is operating on the basis the Red Scarlet Banner Company is willfully committing evil by harvesting and creating the drugs that they are. Thus the people in the trade town are all accomplices who work for the RSBC. But regardless of how evil or uncaring, he is operating by a code of "right and wrong" and that code says all who are against the Fountain must be punished. Since there is no "bible" or "Hammurabi's Code", that leaves it up to Dan's interpretation based on what his people believe to be right and wrong.
At best, I'd say Lawful Neutral. At worst, Lawful Evil.
But, CoS doesn't use the normal alignment system so it's all kinda eh.