Identify the Three-Digit ERG Guide Number

• If you can see the four digit UN/NA number, refer to the ID Number Index in the YELLOW bordered pages
• If you cannot identify the UN/NA number, but know the name of material, search for the material in the BLUE bordered pages
• If you can see a placard or label, refer to the ERG, Table of Markings, Labels and Placards, located on pages eight and nine
• If you do not know the UN ID number, the name of the material, or see a placard or label – and as a last resort, if the container can be identified, refer to Rail Car and Road Trailer Identification Charts located on pages 10-13. Note that some bad train incidents, for example, may have multiple types of tanks involved and be piled up, making it difficult to identify containers
• If you are unable to identify the UN ID number, do not know the name of the material, do not see a placard or label and cannot identify the rail car or road trailer, use Guide 111 in the orange pages until additional information becomes available, then, redo the flowchart once the name of the material or accurate UN ID number is identified

By looking up the known information in the appropriate colored pages, the ERG Guide number can be identified.