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  5. Table 1 - Initial Isolation and Protective Actions Distances

Table 1 - Initial Isolation and Protective Actions Distances

  1. The responder should already have:
    • Identified the material by its ID Number and Name; (if an ID Number cannot be found, use the Name of Material index in the blue-bordered pages to locate that number.)
    • Found the three-digit guide for that material in order to consult the emergency actions recommended jointly with this table;
    • Noted the wind direction.
  2. Look in Table 1 (the green-bordered pages) for the ID Number and Name of the Material involved in the incident. Some ID Numbers have more than one shipping name listed - look for the specific name of the material. (If the shipping name is not known and Table 1 lists more than one name for the same ID Number, use the entry with the largest protective action distances.)
  3. Determine if the incident involves a Small or Large spill and if Day or Night. A Small Spill consists of a release of less than 208 liters (55 US gallons). This generally corresponds to a spill from a single small package (e.g. a drum), a small cylinder, or a small leak from a large package. A Large Spill consists of a release of more than 208 liters (55 US gallons). This usually involves a spill from a large package, or multiple spills from many small packages. Day is any time after sunrise and before sunset. Night is any time between sunset and sunrise.
  4. Look up the Initial Isolation Distance. This distance defines the radius of a zone (Initial Isolation Zone) surrounding the spill in ALL DIRECTIONS. Within this zone, all public should be evacuated (protective clothing and respiratory protection is required in this zone). Persons should be directed to move out of the zone in a direction perpendicular to wind direction (crosswind), and away from the spill, to a minimum distance as prescribed by the Initial Isolation Distance.

    Image describing Initial Isolation Distance

  5. Look up the initial PROTECTIVE ACTION DISTANCE. For a given material, spill size, and whether day or night, Table 1 gives the downwind distance - in kilometers and miles - from the spill/leak source for which protective actions should be considered. For practical purposes, the Protective Action Zone (i.e., the area in which people are at risk of harmful exposure) is a square, whose length and width are the same as the downwind distance shown in Table 1. Protective actions are those steps taken to preserve the health and safety of emergency responders and the public. People in this area should be evacuated and/or sheltered-in-place.
  6. Initiate Protective Actions to the extent possible, beginning with those closest to the spill site and working away from the site in the downwind direction. When a water-reactive TIH (PIH in the US)-producing material is spilled into a river or stream, the source of the toxic gas may move with the current or stretch from the spill point downstream for a substantial distance.

    The shape of the area in which protective actions should be taken (the Protective Action Zone) is shown in this figure. The spill is located at the center of the small circle. The larger circle represents the INITIAL ISOLATION zone around the spill.

Image describing Protective Action Distance
See "Introduction To Green Tables - Initial Isolation And Protective Action Distances" under Factors That May Change the Protective Action Distances
When a product in Table 1 has the mention "(when spilled in water)", refer to Table 2 - Water-Reactive Materials which Produce Toxic Gases for the list of gases produced when these materials are spilled in water.

Call the emergency response telephone number listed on the shipping paper or the appropriate response agency as soon as possible for additional information on the material, safety precautions and mitigation procedures.

Change to imperial units

Small Spills
(From a small package or small leak from a large package)
Large Spills
(From a large package or from many small packages)
First Isolate in all directionsThen Protect persons Downwind duringFirst Isolate in all directionsThen Protect persons Downwind during
IDName of Materialmkmkmmkmkm
  1005   Ammonia, anhydrous300.10.2Refer to Table 3
  1005   Anhydrous ammonia300.10.2Refer to Table 3
  1008   Boron trifluoride300.10.74002.24.8
  1008   Boron trifluoride, compressed300.10.74002.24.8
  1016   Carbon monoxide300.10.22001.24.4
  1016   Carbon monoxide, compressed300.10.22001.24.4
  1017   Chlorine600.31.1Refer to Table 3
  1026   Cyanogen300.10.4600.31.1
  1040   Ethylene oxide300.10.2Refer to Table 3
  1040   Ethylene oxide with Nitrogen300.10.2Refer to Table 3
  1045   Fluorine300.10.21000.52.2
  1045   Fluorine, compressed300.10.21000.52.2
  1048   Hydrogen bromide, anhydrous300.10.21500.92.6
  1050   Hydrogen chloride, anhydrous300.10.3Refer to Table 3
  1051   AC (when used as a weapon)600.3110003.78.4
  1051   Hydrocyanic acid, aqueous solutions, with more than 20% Hydrogen cyanide600.20.93001.12.4
  1051   Hydrogen cyanide, anhydrous, stabilized600.20.93001.12.4
  1051   Hydrogen cyanide, stabilized600.20.93001.12.4
  1052   Hydrogen fluoride, anhydrous300.10.4Refer to Table 3
  1053   Hydrogen sulfide300.10.44002.15.4
  1053   Hydrogen sulphide300.10.44002.15.4
  1061   Methylamine, anhydrous300.10.22000.61.9
  1062   Methyl bromide300.10.11500.30.7
  1064   Methyl mercaptan300.10.32001.13.1
  1067   Dinitrogen tetroxide300.10.44001.23
  1067   Nitrogen dioxide300.10.44001.23
  1069   Nitrosyl chloride300.215003.48.3
  1076   CG (when used as a weapon)1500.83.210007.511.0+
  1076   DP (when used as a weapon)300.20.720012.4
  1076   Phosgene1000.62.550039
  1079   Sulfur dioxide1000.72.2Refer to Table 3
  1079   Sulphur dioxide1000.72.2Refer to Table 3
  1082   Refrigerant gas R-1113300.10.1600.30.7
  1082   Trifluorochloroethylene, stabilized300.10.1600.30.7
  1092   Acrolein, stabilized1001.33.45006.111
  1093   Acrylonitrile, stabilized300.20.51001.12.1
  1098   Allyl alcohol300.20.3600.71.2
  1135   Ethylene chlorohydrin300.10.2600.40.6
  1143   Crotonaldehyde300.10.2600.50.8
  1143   Crotonaldehyde, stabilized300.10.2600.50.8
  1162   Dimethyldichlorosilane (when spilled in water)300.10.2600.51.7
  1163   1,1-Dimethylhydrazine300.20.510011.8
  1163   Dimethylhydrazine, unsymmetrical300.20.510011.8
  1182   Ethyl chloroformate300.10.1600.30.5
  1183   Ethyldichlorosilane (when spilled in water)300.10.2600.62
  1185   Ethyleneimine, stabilized300.20.41500.91.7
  1196   Ethyltrichlorosilane (when spilled in water)300.20.71501.95.6
  1238   Methyl chloroformate300.20.61501.12.1
  1239   Methyl chloromethyl ether600.51.430035.6
  1242   Methyldichlorosilane (when spilled in water)300.10.3600.72.2
  1244   Methylhydrazine300.30.61001.32.1
  1250   Methyltrichlorosilane (when spilled in water)300.10.3600.82.4
  1251   Methyl vinyl ketone, stabilized1000.30.78001.52.6
  1259   Nickel carbonyl1001.44.9100011.0+11.0+
  1295   Trichlorosilane (when spilled in water)300.10.2600.62
  1298   Trimethylchlorosilane (when spilled in water)300.10.2600.51.4
  1305   Vinyltrichlorosilane (when spilled in water)300.10.2600.61.8
  1305   Vinyltrichlorosilane, stabilized (when spilled in water)300.10.2600.61.8
  1340   Phosphorus pentasulfide, free from yellow and white Phosphorus (when spilled in water)300.10.2600.31.3
  1340   Phosphorus pentasulphide, free from yellow and white Phosphorus (when spilled in water)300.10.2600.31.3
  1360   Calcium phosphide (when spilled in water)300.20.630013.7
  1380   Pentaborane600.51.915024.7
  1384   Sodium dithionite (when spilled in water)300.20.5600.62.2
  1384   Sodium hydrosulfite (when spilled in water)300.20.5600.62.2
  1384   Sodium hydrosulphite (when spilled in water)300.20.5600.62.2
  1397   Aluminum phosphide (when spilled in water)600.20.950027.1
  1419   Magnesium aluminum phosphide (when spilled in water)600.20.85001.86.2
  1432   Sodium phosphide (when spilled in water)300.20.63001.34
  1510   Tetranitromethane300.20.3300.40.7
  1541   Acetone cyanohydrin, stabilized (when spilled in water)300.10.11000.31

” + ” means distance can be larger in certain atmospheric conditions

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