What is in the yellow section
In the 2024 edition the yellow section runs from printed page 29 to page 86 and holds 2,771 rows for 1,983 different ID numbers. Each row is an ID number, a guide number and a name of material. 522 rows are highlighted in green, which means the material also has a row in Table 1. The 62 guides the numbers point to are in the orange section.
One number can have many rows. ID 1075, for example, appears 9 times, as Butane, Butylene, Isobutane, Isobutylene, Liquefied petroleum gas, LPG, Petroleum gases, liquefied, Propane, Propylene, all with Guide 115. Scan every row for your number before you move on, because a name can change whether the row is green.
Worked example: the number beats the placard
A cargo tank shows a class 3 placard with 1203 across the middle. The placard alone would point to Guide 127 in the placard table. The yellow section, page 32, says 1203 is Gasoline, Guide 128, not highlighted. So the guide is 128, and the first distance is its immediate precautionary measure: Guide 128's immediate precautionary measure: isolate at least 50 m in all directions. Entering 127 in the drill gets this feedback: "127 is the placard table's guide for this placard. With an ID number, use the yellow index instead: 1203 is Guide 128."
The P after a guide number
Some rows print a P after the guide, as 1040 Ethylene oxide does with Guide 119P. The P warns that the material may polymerize violently, for example when heated or contaminated. The guide page itself is the number without the P. In the drill, a guide typed without its P is still right, with the note: "The index prints 119P. The P warns that the material may polymerize violently; the guide page is still 119."
IDs with more than one guide
Almost every ID number maps to a single guide, but not all. In this edition 4 ID numbers send different names to different guides: 1057 (Guides 115, 128); 3166 (Guides 115, 128); 3171 (Guides 138, 147, 154); 3536 (Guides 138, 147). For these the name decides the guide, so read the whole row. Placardset's timed lookup run leaves them out, because it shows only the number.
Where the numbers come from
The ID number, the proper shipping name and the hazard class all come from the regulations' hazardous materials table, and they appear together on the shipping paper. The guidebook adds the guide number and the green highlight. Placardset's drill set takes its classes from that table and its guides from the yellow section, and a test checks that each name is printed in the index with the same guide.
Common mistakes
- Stopping at the first row for an ID number when the next row, with a different name, is green.
- Reading the guide number as a page number.
- Mixing up neighbouring numbers: 1017 and 1071 are both gases with different guides.
- Dropping the P and forgetting the polymerization warning it carries.
Check any number with the UN number lookup, or race the clock in the timed lookup run.
Sources
Checked on 27 September 2026. Everything here is said in our own words; the guidebook's text is paraphrased, never quoted at length. Where your instructor, your employer's plan or the current printed guidebook says something different, follow them.
- 2024 Emergency Response Guidebook, yellow section (printed pages 28 to 87). The ID number index and its introduction, including the green highlighting and the P suffix; opened 27 September 2026.
- 2024 Emergency Response Guidebook, orange section (printed pages 148 to 279). The guides, including each guide's Evacuation section with its immediate precautionary measure; opened 27 September 2026.
- Hazardous Materials Table, 49 CFR 172.101 (eCFR text as of 1 September 2026). The hazard class and subsidiary hazards of every material in the drill set; opened 27 September 2026.
- Placardset's grader. Every example on this page is computed by the drill's own data and grading at build time, and pinned by a test.