The Standard Carrier Alpha Code (SCAC) is a unique four-letter code used to identify transportation companies by the National Motor Freight Traffic Association (NMFTA). SCAC's are required when doing business with all U.S. Government agencies and with many commercial shippers including those in the automotive, petroleum, forest products and chemical industries. HazMat, intermodal container, rail yard and import/ export loads usually require that you have an SCAC code. You will need an SCAC to register with e-modal to enter many of the sea ports, most notably Baltimore.