That is interesting....Missouri does do testing on oils, coolant, etc. There is a handful of engine oils and coolants that can not be purchased in Missouri. The comments on the engine oils state fail to meet on or more of the following are not allowed to sell in Missouri; product contains used oil, is labeled with the wrong viscosity, or contains less than the declared net contents on the label. But I do not know the scoop on the 303 but could be similar reason for the banning of the product. I would be interested to know the reason as well...