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Rationale for the Development of a List of Regulated Substances Under CEPA Section 200 and their Threshold Quantities

5. Threshold Calculation for Substances in CRAIM List Originating from MIACC Lists

The list of substances and the threshold quantities for toxic substances originating from the MIACC List were based on expert opinion.

These threshold quantities were recalculated using the methodology that the U.S. Environmental Protection Agency used for the RMP. The principle of "Equivalent Harm" was followed. The IDLH published in 1990 were used for assessing toxicity. The 1990 IDLH values were chosen to be consistent with the RMP numbers. Future updates of the threshold quantities could be formulated using appropriate toxicity levels. The detailed calculations are presented in Exhibit 5. A summary is presented in Table 9 for toxics and Table 10 for flammables. It is recommended that the MIACC threshold quantities that are currently based on expert opinion which are difficult to trace and reproduce, be replaced by the calculated thresholds using RMP methodology.

Table 9 - Recalculated Threshold for Toxic Substances in CRAIM List Originating From MIACC Lists
ChemicalCRAIM Threshold Quantity
Tonnes (lbs)
Recalculated Thresholds Quantities Using RMP Methodology  with IDLH 1990 Criteria
Tonnes (lbs)

Notes:

  • 1 1,2-Dichloroethane reclassified as toxic using ERPG-2 (2002)
  • 2 No change
1,2-Dichloroethane150.00 (110,000)6.80 (15,000)
2-Chloroethanol1.00 (2,200)4.50 (10,000)
Allyl Chloride0.45 (1,000)9.10 (20,000)
Carbon monoxide10.00 (22,000)6.80 (15,000)
Chloropicrin0.22 (500)2.27 (5,000)
Chlorosulphonic acid1.00 (2,200)2.27 (5,000)
Cyanogen bromide1.00 (2,200)4.50 (10,000)
Hydrobromic acid2.25 (5,000) 1.13 (2,500)
Ketene0.05 (110)0.22 (500)
Mercury21.00 (2,200)1.00 (2,200)
Methacryloyloxyethyl isocyanate0.05 (1,000)Essentially not in Canadian commerce
Methacrolein (Methacrylaldehyde)0.45 (110)Essentially not in Canadian commerce
Methyl bromide1.15 (2,500) 6.80 (15,000)
Methyl iodide3.40 (7,500)4.50 (10,000)
Methyl vinyl ketone0.05 (1,000)Essentially not in Canadian commerce
Nitrogen dioxide0.11 (220)1.13 (2,500)
Osmium tetroxide0.05 (110)0.22 (500)
Phenol10.00 (22,000)9.10 (20,000)
Stibine0.22 (500)2.27 (5,000)
Tetraethyl lead1.00 (2,200)2.27 (5,000)
Thionyl Chloride0.11 (220)6.80 (15,000)
Trioxychlorofluoride2.25 (5,000)6.80 (15,000)


Table 10 - Recalculated Threshold for Flammable Substances in CRAIM List Originating From MIACC Lists
ChemicalCRAIM Threshold Quantity
Tonnes (lbs)
Recalculated Thresholds Quantities Using RMP Methodology
Tonnes (lbs)

Notes:

  • 1 1,2-Dichloroethane was reclassified as toxic
  • 2 Threshold reflects potential carcinogenic properties.
  • 3 Based on winter gasoline properties
  • 4 No changes
1,2-Dichloroethane150 (110,000) 
Benzene10 (22,000)10 (22,000)2
Gasoline50 (110,000)150 (330,000)3
Cyclohexane50 (110,000)550 (1,210,000)
Ethylbenzene50 (110,000)7 000 (15,400,000)
Ethylbenzene50 (110,000)7 000 (15,400,000)
Natural gas4.5 (10,000)4.5 (10,000)4
Petroleum ether50 (110,000) 50 (110,000)4
Dimethyl sulphide10 (22,000)150 (330,000)
t-Butylamine10 (22,000)150 (330,000)
Toluene50 (110,000)2 500 (5,500,000)
Xylene50 (110,000)8 000 (17,600,000)