The Special Investigations Division prepared a report for Rep. Waxman that identified previously unreported pollution from oil refineries as a major source of smog-forming toxic air pollutants. Audits performed by EPA and analyzed in the report reveal that oil refineries emit vast quantities of unreported emissions from leaking valves. Unlike other pollution sources -- which can cost up to $20,000 per ton to control -- fixing the leaking valves does not require new technology or expensive retrofit equipment. In many instances, the pollution can be eliminated simply by tightening the valves with a wrench.