Light brown sugar is exposed to heat to evaporate the cane juice, leaving behind the molasses. The molasses usually has a strong scent, which can even soak up some of the residual smoke from the heating process. It isn't unusual to smell a 'smokey' scent, especially if you are not used to eating sugar with the molasses still in it. Molasses can pick up all kinds of strange scents which get concentrated by the heating process, originating both from the growing sugar cane environment and the heating method itself. It is part of its 'charm.' I doubt any aspect of it is dangerous, though if you are eating molasses often, you should be aware that it has been known to pick up large quantities of vitamins and minerals including iron, but also tends to absorb some of the chemicals used in the extraction process, if it is chemically extracted rather than only using natural heating methods.
The company who sells it can probably tell you which method is used, if you have any ongoing concerns.