WASHINGTON, Dec. 13 -- Sen. Charles E. Grassley, R-Iowa, issued the following news release: Sen. Chuck Grassley (R-Iowa), a member of the Senate Finance and Agriculture Committees, joined Sen. Joni Ernst (R-Iowa) and bipartisan colleagues in demanding answers from the Environmental Protection Agency (EPA) regarding its process for verifying the authenticity of used cooking oil (UCO) imports. Grassley and colleagues in June first probed EPA, along with Customs and Border Protection (CBP), abou  more