Superfund Enhancement Act of 2019 This bill reinstates and increases the Hazardous Substance Superfund financing rate from 9.7 cents to 15.8 cents and allows certain small businesses to expense up to $10,000 of the costs of relocating a trade or business carried on in a location on or near a site proposed for inclusion on the national priorities list under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980. The bill directs the Small Business Administration (SBA) to make disaster loans to small business concerns whose principal place of business is located on a Superfund site and authorizes the SBA to make economic injury loans to such business concerns. The bill also modifies the definition of crude oil for excise tax purposes.