Rationale for list of regulated substances under Canadian Environmental Protection Act: chapter 5


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
Chemical CRAIM 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-Dichloroethane1 50.00 (110,000) 6.80 (15,000)
2-Chloroethanol 1.00 (2,200) 4.50 (10,000)
Allyl Chloride 0.45 (1,000) 9.10 (20,000)
Carbon monoxide 10.00 (22,000) 6.80 (15,000)
Chloropicrin 0.22 (500) 2.27 (5,000)
Chlorosulphonic acid 1.00 (2,200) 2.27 (5,000)
Cyanogen bromide 1.00 (2,200) 4.50 (10,000)
Hydrobromic acid 2.25 (5,000)  1.13 (2,500)
Ketene 0.05 (110) 0.22 (500)
Mercury2 1.00 (2,200) 1.00 (2,200)
Methacryloyloxyethyl isocyanate 0.05 (1,000) Essentially not in Canadian commerce
Methacrolein (Methacrylaldehyde) 0.45 (110) Essentially not in Canadian commerce
Methyl bromide 1.15 (2,500)  6.80 (15,000)
Methyl iodide 3.40 (7,500) 4.50 (10,000)
Methyl vinyl ketone 0.05 (1,000) Essentially not in Canadian commerce
Nitrogen dioxide 0.11 (220) 1.13 (2,500)
Osmium tetroxide 0.05 (110) 0.22 (500)
Phenol 10.00 (22,000) 9.10 (20,000)
Stibine 0.22 (500) 2.27 (5,000)
Tetraethyl lead 1.00 (2,200) 2.27 (5,000)
Thionyl Chloride 0.11 (220) 6.80 (15,000)
Trioxychlorofluoride 2.25 (5,000) 6.80 (15,000)


Table 10 - Recalculated Threshold for Flammable Substances in CRAIM List Originating From MIACC Lists
Chemical CRAIM 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-Dichloroethane1 50 (110,000)  
Benzene 10 (22,000) 10 (22,000)2
Gasoline 50 (110,000) 150 (330,000)3
Cyclohexane 50 (110,000) 550 (1,210,000)
Ethylbenzene 50 (110,000) 7 000 (15,400,000)
Ethylbenzene 50 (110,000) 7 000 (15,400,000)
Natural gas 4.5 (10,000) 4.5 (10,000)4
Petroleum ether 50 (110,000)  50 (110,000)4
Dimethyl sulphide 10 (22,000) 150 (330,000)
t-Butylamine 10 (22,000) 150 (330,000)
Toluene 50 (110,000) 2 500 (5,500,000)
Xylene 50 (110,000) 8 000 (17,600,000)


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