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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
  1556   MD (when used as a weapon)3001.64.3100011.0+11.0+
  1556   Methyldichloroarsine1001.323003.24.2
  1556   PD (when used as a weapon)600.40.43001.61.6
  1560   Arsenic chloride300.20.310011.4
  1560   Arsenic trichloride300.20.310011.4
  1569   Bromoacetone300.41.21501.83.4
  1580   Chloropicrin600.51.22002.23.6
  1581   Chloropicrin and Methyl bromide mixture300.10.63002.15.9
  1581   Methyl bromide and Chloropicrin mixture300.10.63002.15.9
  1582   Chloropicrin and Methyl chloride mixture300.10.4600.41.7
  1582   Methyl chloride and Chloropicrin mixture300.10.4600.41.7
  1583   Chloropicrin mixture, n.o.s.600.51.22002.23.6
  1589   CK (when used as a weapon)8005.311.0+100011.0+11.0+
  1589   Cyanogen chloride, stabilized3001.86.210009.411.0+
  1595   Dimethyl sulfate300.20.2600.50.6
  1595   Dimethyl sulphate300.20.2600.50.6
  1605   Ethylene dibromide300.10.1300.10.2
  1612   Compressed gas and hexaethyl tetraphosphate mixture1000.82.74003.58.1
  1612   Hexaethyl tetraphosphate and compressed gas mixture1000.82.74003.58.1
  1613   Hydrocyanic acid, aqueous solution, with not more than 20% Hydrogen cyanide300.10.11000.51.1
  1613   Hydrogen cyanide, aqueous solution, with not more than 20% Hydrogen cyanide300.10.11000.51.1
  1614   Hydrogen cyanide, stabilized (absorbed)600.20.61500.51.6
  1647   Ethylene dibromide and Methyl bromide mixture, liquid300.10.11500.30.7
  1647   Methyl bromide and Ethylene dibromide mixture, liquid300.10.11500.30.7
  1660   Nitric oxide300.10.51000.52.2
  1660   Nitric oxide, compressed300.10.51000.52.2
  1670   Perchloromethyl mercaptan300.20.31000.61.1
  1672   Phenylcarbylamine chloride300.20.2600.50.7
  1680   Potassium cyanide (when spilled in water)300.10.21000.31.2
  1680   Potassium cyanide, solid (when spilled in water)300.10.21000.31.2
  1689   Sodium cyanide (when spilled in water)300.10.21000.41.4
  1689   Sodium cyanide, solid (when spilled in water)300.10.21000.41.4
  1694   CA (when used as a weapon)300.10.41000.52.6
  1695   Chloroacetone, stabilized300.10.2300.40.6
  1697   CN (when used as a weapon)300.10.2600.31.2
  1698   Adamsite (when used as a weapon)300.10.3600.31.4
  1698   DM (when used as a weapon)300.10.3600.31.4
  1699   DA (when used as a weapon)300.20.83001.97.5
  1716   Acetyl bromide (when spilled in water)300.10.2300.40.9
  1717   Acetyl chloride (when spilled in water)300.10.31000.92.5
  1722   Allyl chlorocarbonate1000.30.84001.42.4
  1722   Allyl chloroformate1000.30.84001.42.4
  1724   Allyltrichlorosilane, stabilized (when spilled in water)300.10.2600.51.7
  1725   Aluminum bromide, anhydrous (when spilled in water)300.10.1300.10.4
  1726   Aluminum chloride, anhydrous (when spilled in water)300.10.3600.52
  1728   Amyltrichlorosilane (when spilled in water)300.10.2600.51.7
  1732   Antimony pentafluoride (when spilled in water)300.10.510013.8
  1741   Boron trichloride (when spilled on land)300.10.31000.61.3
  1741   Boron trichloride (when spilled in water)300.10.41001.13.5
  1744   Bromine600.82.33003.77.5
  1744   Bromine, solution600.82.33003.77.5
  1744   Bromine, solution (Inhalation Hazard Zone A)600.82.33003.77.5
  1744   Bromine, solution (Inhalation Hazard Zone B)300.10.2300.30.5
  1745   Bromine pentafluoride (when spilled on land)600.82.44004.910.2
  1745   Bromine pentafluoride (when spilled in water)300.10.51001.13.9
  1746   Bromine trifluoride (when spilled on land)300.10.2300.30.5
  1746   Bromine trifluoride (when spilled in water)300.10.510013.7
  1747   Butyltrichlorosilane (when spilled in water)300.10.2600.51.6
  1749   Chlorine trifluoride600.31.13001.44.1
  1752   Chloroacetyl chloride (when spilled on land)300.30.61001.11.9
  1752   Chloroacetyl chloride (when spilled in water)300.10.1300.30.8
  1753   Chlorophenyltrichlorosilane (when spilled in water)300.10.1300.30.9
  1754   Chlorosulfonic acid (with or without sulfur trioxide mixture) (when spilled on land)300.10.1300.20.3
  1754   Chlorosulfonic acid (with or without sulfur trioxide mixture) (when spilled in water)300.10.3600.72.2
  1754   Chlorosulphonic acid (with or without sulphur trioxide mixture) (when spilled on land)300.10.1300.20.3
  1754   Chlorosulphonic acid (with or without sulphur trioxide mixture) (when spilled in water)300.10.3600.72.2
  1758   Chromium oxychloride (when spilled in water)300.10.1300.20.7
  1762   Cyclohexenyltrichlorosilane (when spilled in water)300.10.2300.41.2
  1763   Cyclohexyltrichlorosilane (when spilled in water)300.10.2300.41.3
  1765   Dichloroacetyl chloride (when spilled in water)300.10.1300.30.9

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

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