Why does America not use sea salt and uses salt from some other source.The whole world uses sea salt.?

Sea salt is the most cheapest commodity in the whole world but in the US its very expensive and sold at a premium price. Sea salt is more healthier than the salt sold in the US. Because of all the additives and presavatives and artiificial sweetners 1000 are prone to Cancer and the FDA approves all these dangerous substitute and smoe Medications too!!