By John S. McClenahen Two months after U.S. President George W. Bush imposed tariffs as high as 30% on imported steel, Sen. John D. "Jay" Rockefeller, D-W. Va., and a dozen of his colleagues are protesting exemptions to the White House action. One estimate is that nearly 200 exemptions, accounting for about one-third of steel imports, have already been granted for products not made by U.S. companies. "We are very concerned about reports that the Administration is considering granting a significant number of additional product exclusions," Rockefeller wrote to the President last week. "Many times there appear to be no domestic suppliers of a product because domestic manufacturers have been driven from the market by unfair dumping or import surges, but, in fact, domestic producers are eager to resume production if our trade laws can provide some stability in the market," Rockefeller said. "Product exclusions cannot be used as a loophole to defeat the purpose of trade remedies," he insisted.