How to read the table

  1. Confirm the entry is green. Only entries highlighted in green in the yellow or blue section have a Table 1 row. For the rest, use the guide's immediate precautionary distance.
  2. Find the row. Table 1 is in ID number order. Find the ID and check the name, because some materials have one row for a land spill and another for a spill into water.
  3. Choose the spill size. A small spill is a small package or a small leak from a large package; a large spill is a large package or many small ones.
  4. Read the isolation distance. The first figure in the chosen columns is how far to isolate the area in all directions.
  5. Read the protective action distance. Then choose day or night and read how far downwind people should be protected, by evacuating or sheltering in place.

Worked example: chlorine

1017 Chlorine is highlighted on page 29 of the yellow section, and its Table 1 row is on printed page 290. For a small spill: isolate 60 m (200 ft), then protect 0.3 km (0.2 mi) downwind by day or 1.5 km (0.9 mi) at night. For a large spill the row says Refer to Table 3.

A trainee who reads the day figure for a night leak gets this from the drill: "Protect: night gives 1.5 km; you wrote 0.3. That is the day column."

Worked example: phosgene, the large night figure

For 1076 Phosgene, a large spill means isolating 500 m and protecting 9.5 km downwind at night, against 2.5 km for a small spill. On the two Table 1 pages Placardset carries, the largest night figure is 1092 Acrolein, stabilized: 11.1 km (6.9 mi) after isolating 600 m.

The rows Placardset carries

The drill uses the 41 rows on printed pages 290 and 291 (33 ID numbers), typed in and checked against the book's own text. Every highlighted material in the drill set is among them, so the distance you are asked for is always in the table below. Rows that say Refer to Table 3 for a large spill: 1005, 1017, 1040, 1050, 1052, 1079.

Table 1, initial isolation and protective action distances (printed pages 290 and 291)
IDGuideName of materialSmall spill: isolateSmall: protect daySmall: protect nightLarge spill: isolateLarge: protect dayLarge: protect night
1005125Ammonia, anhydrous30 m (100 ft)0.1 km (0.1 mi)0.2 km (0.1 mi)Refer to Table 3
1005125Anhydrous ammonia30 m (100 ft)0.1 km (0.1 mi)0.2 km (0.1 mi)Refer to Table 3
1008125Boron trifluoride30 m (100 ft)0.2 km (0.1 mi)0.7 km (0.5 mi)400 m (1250 ft)2.4 km (1.5 mi)4.7 km (2.9 mi)
1008125Boron trifluoride, compressed30 m (100 ft)0.2 km (0.1 mi)0.7 km (0.5 mi)400 m (1250 ft)2.4 km (1.5 mi)4.7 km (2.9 mi)
1016119Carbon monoxide, compressed30 m (100 ft)0.1 km (0.1 mi)0.2 km (0.1 mi)200 m (600 ft)1.2 km (0.7 mi)3.9 km (2.4 mi)
1017124Chlorine60 m (200 ft)0.3 km (0.2 mi)1.5 km (0.9 mi)Refer to Table 3
1026119Cyanogen30 m (100 ft)0.1 km (0.1 mi)0.4 km (0.3 mi)60 m (200 ft)0.3 km (0.2 mi)1.1 km (0.7 mi)
1040119PEthylene oxide30 m (100 ft)0.1 km (0.1 mi)0.2 km (0.2 mi)Refer to Table 3
1040119PEthylene oxide with nitrogen30 m (100 ft)0.1 km (0.1 mi)0.2 km (0.2 mi)Refer to Table 3
1045124Fluorine, compressed30 m (100 ft)0.1 km (0.1 mi)0.2 km (0.1 mi)100 m (300 ft)0.5 km (0.3 mi)2.3 km (1.4 mi)
1048125Hydrogen bromide, anhydrous30 m (100 ft)0.1 km (0.1 mi)0.2 km (0.2 mi)150 m (500 ft)1 km (0.7 mi)3.2 km (2 mi)
1050125Hydrogen chloride, anhydrous30 m (100 ft)0.1 km (0.1 mi)0.3 km (0.2 mi)Refer to Table 3
1051117PHydrogen cyanide, stabilized60 m (200 ft)0.2 km (0.1 mi)0.7 km (0.4 mi)200 m (600 ft)0.7 km (0.5 mi)1.8 km (1.1 mi)
1052125Hydrogen fluoride, anhydrous30 m (100 ft)0.1 km (0.1 mi)0.5 km (0.3 mi)Refer to Table 3
1053117Hydrogen sulfide30 m (100 ft)0.1 km (0.1 mi)0.5 km (0.3 mi)400 m (1250 ft)2.4 km (1.5 mi)6.3 km (4 mi)
1053117Hydrogen sulphide30 m (100 ft)0.1 km (0.1 mi)0.5 km (0.3 mi)400 m (1250 ft)2.4 km (1.5 mi)6.3 km (4 mi)
1061118Methylamine, anhydrous30 m (100 ft)0.1 km (0.1 mi)0.2 km (0.1 mi)200 m (600 ft)0.6 km (0.4 mi)2.1 km (1.3 mi)
1062123Methyl bromide30 m (100 ft)0.1 km (0.1 mi)0.1 km (0.1 mi)150 m (500 ft)0.3 km (0.2 mi)0.7 km (0.5 mi)
1064117Methyl mercaptan30 m (100 ft)0.1 km (0.1 mi)0.3 km (0.2 mi)200 m (600 ft)1.3 km (0.8 mi)3.9 km (2.4 mi)
1067124Dinitrogen tetroxide30 m (100 ft)0.1 km (0.1 mi)0.4 km (0.3 mi)400 m (1250 ft)1.4 km (0.9 mi)3.3 km (2.1 mi)
1067124Nitrogen dioxide30 m (100 ft)0.1 km (0.1 mi)0.4 km (0.3 mi)400 m (1250 ft)1.4 km (0.9 mi)3.3 km (2.1 mi)
1069125Nitrosyl chloride30 m (100 ft)0.2 km (0.2 mi)1 km (0.7 mi)800 m (2500 ft)4.3 km (2.7 mi)9.6 km (6 mi)
1076125Phosgene100 m (300 ft)0.6 km (0.4 mi)2.5 km (1.6 mi)500 m (1500 ft)3 km (1.9 mi)9.5 km (5.9 mi)
1079125Sulfur dioxide100 m (300 ft)0.6 km (0.4 mi)2.6 km (1.6 mi)Refer to Table 3
1079125Sulphur dioxide100 m (300 ft)0.6 km (0.4 mi)2.6 km (1.6 mi)Refer to Table 3
1082119PRefrigerant gas R-111330 m (100 ft)0.1 km (0.1 mi)0.1 km (0.1 mi)60 m (200 ft)0.4 km (0.3 mi)0.7 km (0.5 mi)
1082119PTrifluorochloroethylene, stabilized30 m (100 ft)0.1 km (0.1 mi)0.1 km (0.1 mi)60 m (200 ft)0.4 km (0.3 mi)0.7 km (0.5 mi)
1092131PAcrolein, stabilized100 m (300 ft)1.3 km (0.8 mi)3.5 km (2.2 mi)600 m (2000 ft)6.8 km (4.2 mi)11.1 km (6.9 mi)
1093131PAcrylonitrile, stabilized30 m (100 ft)0.2 km (0.2 mi)0.6 km (0.4 mi)100 m (300 ft)1.3 km (0.8 mi)2.3 km (1.5 mi)
1098131Allyl alcohol30 m (100 ft)0.2 km (0.1 mi)0.3 km (0.2 mi)60 m (200 ft)0.8 km (0.5 mi)1.2 km (0.8 mi)
1135131Ethylene chlorohydrin30 m (100 ft)0.1 km (0.1 mi)0.1 km (0.1 mi)30 m (100 ft)0.1 km (0.1 mi)0.1 km (0.1 mi)
1143131PCrotonaldehyde30 m (100 ft)0.1 km (0.1 mi)0.2 km (0.1 mi)60 m (200 ft)0.5 km (0.3 mi)0.7 km (0.5 mi)
1143131PCrotonaldehyde, stabilized30 m (100 ft)0.1 km (0.1 mi)0.2 km (0.1 mi)60 m (200 ft)0.5 km (0.3 mi)0.7 km (0.5 mi)
1162155Dimethyldichlorosilane (when spilled in water)30 m (100 ft)0.1 km (0.1 mi)0.1 km (0.1 mi)30 m (100 ft)0.4 km (0.2 mi)1.2 km (0.8 mi)
1163131Dimethylhydrazine, unsymmetrical30 m (100 ft)0.2 km (0.1 mi)0.5 km (0.3 mi)100 m (300 ft)1 km (0.7 mi)1.8 km (1.1 mi)
1182155Ethyl chloroformate30 m (100 ft)0.2 km (0.1 mi)0.3 km (0.2 mi)60 m (200 ft)0.6 km (0.4 mi)0.9 km (0.6 mi)
1183139Ethyldichlorosilane (when spilled in water)30 m (100 ft)0.1 km (0.1 mi)0.1 km (0.1 mi)60 m (200 ft)0.5 km (0.3 mi)1.5 km (0.9 mi)
1185131PEthyleneimine, stabilized30 m (100 ft)0.2 km (0.1 mi)0.5 km (0.3 mi)200 m (600 ft)1 km (0.6 mi)1.8 km (1.1 mi)
1196155Ethyltrichlorosilane (when spilled in water)30 m (100 ft)0.1 km (0.1 mi)0.5 km (0.3 mi)150 m (500 ft)1.8 km (1.2 mi)3.7 km (2.3 mi)
1238155Methyl chloroformate30 m (100 ft)0.2 km (0.2 mi)0.5 km (0.4 mi)150 m (500 ft)1.2 km (0.7 mi)2.2 km (1.4 mi)
1239131Methyl chloromethyl ether60 m (200 ft)0.5 km (0.3 mi)1.5 km (1 mi)300 m (1000 ft)3.4 km (2.1 mi)5.7 km (3.6 mi)

Entries that are not highlighted

Most entries are not green. For those, the first distance is in the orange guide, under Evacuation: an immediate precautionary measure to isolate the spill or leak area in all directions. Across the 62 guides the figures are:

For a large spill, most guides also say to consider a larger downwind evacuation, and with a fire, to isolate a tank or rail car for a much greater distance.

Common mistakes

Practise the columns in the daily drill, which always shows the table, or look up any highlighted ID in the UN number lookup.

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.

Frequently asked questions

Why is the night distance larger?

Air near the ground mixes less at night, so a toxic cloud stays concentrated farther downwind. Table 1 gives separate day and night columns for that reason.

What does Refer to Table 3 mean?

For large spills of six common toxic gases, the distance depends on the container and the wind, so Table 1 sends you to Table 3, which gives distances by container type and wind speed.

What if the material is on fire?

Use the orange guide's evacuation distances for the fire first. Table 1 is then used downwind for material still being released.

Does Table 1 apply to every material?

No. Only the green highlighted entries, which are toxic by inhalation or give off toxic gas in water. For the rest, the orange guide gives the immediate precautionary distance.