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

3. Development of RMP and MIACC Lists

3.1. EPA Risk Management Program Lists

The U.S. EPA process for identifying hazardous substances for emergency measures was based primarily on concerns of air toxicity and physical damage (air blast effects). EPA did not include specific criteria for environmental impacts. However the impact on environmental receptors must be identified.

Environmental receptors are defined as natural areas such as national parks, forests, or monuments: officially designated wildlife sanctuaries; preserves, refuges, or areas; and Federal wilderness areas. Only environmental receptors that can be identified on local U.S. Geological Survey need to be considered. It is required to locate each of these specifically. It is only required to check off in the RMP which specific types of areas are in the circle of specified consequences. If any part of one of these receptors is within the circle, it must be noted on the RMP.

EPA has adopted under the RMP a list of 77 toxic substances with threshold quantities (TQ) which are function of the toxicity of the substance and its volatility (Table 2) and a list of 63 flammable substances (gases and volatile liquids) with one TQ of 4.5 metric tons (10,000 pounds) (Table 3).

The U.S. EPA proposed to include commercial explosives defined by the Department of Transportation (DOT) as Division 1.1 (explosives with mass explosion hazard) with a threshold quantity of 5,000 pounds. However, explosives were not included in the final list because they are regulated by several agencies and organizations such as the Bureau of Alcohol, Tobacco, and Firearms (BATF), the Department of Transportation (DOT), the Occupational Safety and Health Administration (OSHA), the Mine Safety and Health Administration (MSHA), the Department of Defense (DOD) and the International Maritime Organization (IMO).

Toxic substances were included on the list based on their toxicity, physical state, vapour pressure, and accident history.

The minimum vapour pressure for chemicals to be included on the EPA list is 10 millimetres of mercury (mm Hg) (with the exception of toluene diisocyanate which has a lower vapour pressure and which was listed as required by U.S. Congress).

Figure 1 - Development of CRAIM List
Development of CRAIM List

Description

The acute toxicity criteria used are:

  1. Inhalation LC50 ≤ 0.5 milligrams per litre of air (for exposure time 4 ≤ hours), or
  2. Dermal LD50 ≤ 25 milligrams per kilogram of body weight where LC50 is the median concentration in air at which 50 percent of the test animals died, and LD50 is the median lethal dose that killed 50 percent of the test animals. In the absence of LC50 or LD50 data, LCLo or LDLo data were used for listing, where LCLo is the lethal concentration low, or lowest concentration in air at which any of the test animals died.
  3. A vapour pressure of 10 millimetres of mercury (mm Hg) was used as a baseline. Toxic gases and liquid with a vapour pressure of 10 mm Hg or higher under ambient conditions were considered for listing.
  4. Only toxic chemicals in commercial production, verified through EPA's Toxic Substances Control Act (TSCA) Chemical Inventory, were included on the list.
  5. The U.S. EPA Agency also looked at other data sources including a combination of toxicity and history of accidents involving death or injury.

U.S. EPA threshold quantities were set for toxic substances based on a ranking method that considers toxicity and volatility of the chemicals using the principle of "Equivalence of Harm". EPA assigned identical thresholds to chemicals with similar ranking scores. TQs of 0.22 metric tons (500 lbs), 0.45 metric tons (1,000 lbs), 1.13 metric ton (2,500 lbs), 2.27 metric tons (5,000 lbs), 4.50 metric tons (10,000 lbs), 6.80 metric tons (15,000 lbs) and 9.10 metric tons (20,000 lbs).

Table 2 - Toxic Substances Listed In the Risk Management Program with Threshold Quantities
CAS NumberChemical NameEPA Threshold Tonnes (lbs)
107-02-8Acrolein2.27 (5,000)
107-13-1Acrylonitrile9.10 (20,000)
814-68-6Acryloyl chloride (Acrylyl chloride)2.27 (5,000)
107-18-6Allyl alcohol6.80 (15,000)
107-11-9Allylamine4.50 (10,000)
7664-41-7Ammonia (anhydrous)4.50 (10,000)
7664-41-7Ammonia (aqueous solution, conc 20% or greater)9.10 (20,000)
7784-34-1Arsenous trichloride6.80 (15,000)
7784-42-1Arsine0.45 (1,000)
10294-34-5Boron trichloride2.27 (5,000)
7637-07-2Boron trifluoride2.27 (5,000)
7726-95-6Bromine4.50 (10,000)
75-15-0Carbon disulfide9.10 (20,000)
7782-50-5Chlorine1.13 (2,500)
10049-04-4Chlorine dioxide0.45 (1,000)
67-66-3Chloroform9.10 (20,000)
542-88-1Bis(chloromethyl ether) [Dichlorodimethyl ether]0.45 (1,000)
107-30-2Chloromethyl methyl ether2.27 (5,000)
4170-30-3Crotonaldehyde9.10 (20,000)
123-73-9Crotonaldehyde, (E)-9.10 (20,000)
506-77-4Cyanogen chloride4.50 (10,000)
108-91-8Cyclohexylamine6.80 (15,000)
19287-45-7Diborane1.13 (2,500)
75-78-5Dimethyldichlorosilane2.27 (5,000)
57-14-7Dimethylhydrazine6.80 (15,000)
106-89-8Epichlorohydrin9.10 (20,000)
107-15-3Ethylenediamine9.10 (20,000)
151-56-4Ethyleneimine4. 50 (10,000)
75-21-8Ethylene oxide4. 50 (10,000)
7782-41-4Fluorine0.45 (1,000)
50-00-0Formaldehyde solution6. 80 (15,000)
110-00-9Furan2.27 (5,000)
302-01-2Hydrazine6.80 (15,000)
7647-01-0Hydrochloric acid (solution, conc 37% or greater)6.80 (15,000)
74-90-8Hydrocyanic acid1.13 (2,500)
7647-01-0Hydrogen chloride (anhydrous)2. 27 (5,000)
7664-39-3Hydrogen fluoride/Hydrofluoric acid (conc 50% or greater)0.45 (1,000)
7783-07-5Hydrogen selenide0.22 (500)
7783-06-4Hydrogen sulphide0.45 (1,000)
13463-40-6Iron pentacarbonyl1.13 (2,500)
78-82-0Isobutyronitrile9.10 (20,000)
108-23-6Isopropyl chloroformate6.80 (15,000)
126-98-7Methacrylonitrile4.50 (10,000)
74-87-3Methyl chloride4.50 (10,000)
79-22-1Methyl chloroformate2.27 (5,000)
60-34-4Methyl hydrazine6.80 (15,000)
624-83-9Methyl isocyanate4.50 (10,000)
74-93-1Methyl mercaptan4.50 (10,000)
556-64-9Methyl thiocyanate9.10 (20,000)
75-79-6Methyltrichlorosilane2.27 (5,000)
13463-39-3Nickel carbonyl0.45 (1,000)
7697-37-2Nitric acid (conc 80% or greater)6.80 (15,000)
10102-43-9Nitric oxide4.50 (10,000)
7664-93-9Oleum (Fuming sulfuric acid)4.50 (10,000)
79-21-0Peracetic acid4.50 (10,000)
594-42-3Trichloromethanesulfenyl chloride (Perchloromethylmercaptan)4.50 (10,000)
75-44-5Phosgene0.22 (500)
7803-51-2Phosphine2.27 (5,000)
10025-87-3Phosphorus oxychloride2.27 (5,000)
7719-12-2Phosphorus trichloride6.80 (15,000)
110-89-4Piperidine6.80 (15,000)
107-12-0Propionitrile4.50 (10,000)
109-61-5Propyl chloroformate6.80 (15,000)
75-55-8Propyleneimine4.50 (10,000)
75-56-9Propylene oxide4.50 (10,000)
7446-09-5Sulphur dioxide2.25 (5,000)
7783-60-0Sulphur tetrafluoride1.13 (2,500)
7446-11-9Sulphur trioxide4.50 (10,000)
75-74-1Tetramethyl lead4.50 (10,000)
509-14-9Tetranitromethane4.50 (10,000)
7550-45-0Titanium tetrachloride1.14 (2,500)
584-84-9Toluene-2,4-diisocyanate4.50 (10,000)
91-08-7Toluene-2,6-diisocyanate4.50 (10,000)
26471-62-5Toluene diisocyanate (Unspecified isomer)4.50 (10,000)
75-77-4Trichloromethylsilane4.50 (10,000)
108-05-4Vinyl acetate monomer6.80 (15,000)


Flammable gases and volatile flammable liquids were included on the list based on the flash point and boiling point criteria used by the National Fire Protection Association (NFPA) for the highest hazard ranking (flash point below 73°F (22.8°C)) and boiling point below 100°F (37.8°C)5. Only flammable substances in commercial production were listed.

The threshold quantity for flammable substances was set at 4.5 metric tons (10,000 pounds) based on the potential power of a vapour cloud explosion.

Some chemicals are toxic and flammable. The ranking process took both criteria into account and TQ was set in accordance with the toxic index that was calculated. Toxic and flammable chemicals that had a toxic index that would have resulted in TQs in excess of 10,000 pounds were defaulted to 4.50 metric tons (10,000 lbs).

Explosives in Class 1.1, classified by the Department of Transportation (DOT), were proposed for listing based on their potential to detonate. The threshold quantity for explosives was set at 2.27 metric tons (5,000 pounds) because a detonation of this quantity could yield blast wave overpressure of 3.0 pounds per square inch (psi) at a distance of 100 metres from the blast site and could have potentially lethal effects in the community beyond the fence line. However, explosives were not included in the final list because several agencies and organizations regulate them. The criteria were retained by CRAIM with 3 substances that can, under some circumstances, behave as explosives: sodium chlorate, ammonium perchlorate and hydrogen peroxide. Explosives class 1.1 were removed from the list since they are governed by a specific regulation.

EPA proposed to apply the threshold quantity to the maximum potential total quantity of a substance in a process. This definition would apply to the maximum total quantity, at any one time, in a single vessel in a group of interconnected vessels or in several vessels that could potentially be involved at one time in an accidental release.

The TQs were set taking into account the potential theoretical acute impact on people for a one accidental exposure. Toxicity and explosion consequences were also considered.

Table 3 - Flammable Substances Listed In the Risk Management Program with Threshold Quantities
CAS NumberChemical NameEPA Threshold Tonnes (lbs)
75-35-41,1-Dichloroethylene4.50 (10,000)
75-37-61,1-Difluoroethane4.50 (10,000)
75-38-71,1-Difluoroethene4.50 (10,000)
106-99-01,3-Butadiene4.50 (10,000)
504-60-91,3-Pentadiene4.50 (10,000)
106-98-91-Butene4.50 (10,000)
590-21-61-Chloro-1-propene4.50 (10,000)
109-67-11-Pentene4.50 (10,000)
74-99-71-Propyne4.50 (10,000)
107-01-72-Butene4.50 (10,000)
557-98-22-Chloro-1-propene4.50 (10,000)
75-29-62-Chloropropane4.50 (10,000)
563-46-22-Methyl-1-butene4.50 (10,000)
563-45-13-Methyl-1-butene4.50 (10,000)
75-07-0Acetaldehyde4.50 (10,000)
74-86-2Acetylene4.50 (10,000)
598-73-2Bromotrifluoroethylene4.50 (10,000)
106-97-8Butane4.50 (10,000)
25167-67-3Butylene4.50 (10,000)
79-38-9Chlorotrifluoroethylene4.50 (10,000)
590-18-1Cis-2-butene4.50 (10,000)
627-20-3Cis-2-pentene4.50 (10,000)
460-19-5Cyanogen4.50 (10,000)
75-19-4Cyclopropane4.50 (10,000)
7791-21-1Dichlorine oxide4.50 (10,000)
4109-96-0Dichlorosilane4.50 (10,000)
60-29-7Diethyl ether4.50 (10,000)
115-10-6Dimethyl ether4.50 (10,000)
124-40-3Dimethylamine4.50 (10,000)
74-84-0Ethane4.50 (10,000)
107-00-6Ethyl acetylene4.50 (10,000)
75-00-3Ethyl chloride4.50 (10,000)
75-08-1Ethyl mercaptan4.50 (10,000)
109-95-5Ethyl nitrite4.50 (10,000)
109-92-2Ethyl vinyl ether4.50 (10,000)
75-04-7Ethylamine4.50 (10,000)
74-85-1Ethylene4.50 (10,000)
1333-74-0Hydrogen4.50 (10,000)
75-28-5Isobutane4.50 (10,000)
115-11-7Isobutylene4.50 (10,000)
78-78-4Isopentane4.50 (10,000)
78-79-5Isoprene4.50 (10,000)
75-31-0Isopropylamine4.50 (10,000)
74-82-8Methane4.50 (10,000)
107-31-3Methyl formate4.50 (10,000)
75-89-5Methylamine4.50 (10,000)
463-82-1Neopentane4.50 (10,000)
109-66-0n-Pentane4.50 (10,000)
463-49-0Propadiene4.50 (10,000)
74-98-6Propane4.50 (10,000)
115-07-1Propylene4.50 (10,000)
7803-62-5Silane4.50 (10,000)
116-14-3Tetrafluoroethylene4.50 (10,000)
75-76-3Tetramethylsilane4.50 (10,000)
624-64-6Trans-2-butene4.50 (10,000)
646-04-8Trans-2-pentene4.50 (10,000)
10025-78-2Trichlorosilane4.50 (10,000)
75-50-3Trimethylamine4.50 (10,000)
689-97-4Vinyl acetylene4.50 (10,000)
75-02-5Vinyl fluoride4.50 (10,000)
107-25-5Vinyl methyl ether4.50 (10,000)


3.2. MIACC Lists

The development of lists of hazardous substances initiated in 1991 by the Working Group 1 of the Major Industrial Council of Canada (MIACC), was a multistakeholder process. Three lists were developed:

  • MIACC List 1 - Priority Hazardous Substances
  • MIACC List 2 - Hazardous Substances
  • MIACC List 3 - Environmentally Hazardous Substances.

List 1 is a short list of "top priority" substances commonly found in Canada both in fixed facilities and transport situations. An accidental release involving a List 1 substance, at or above the specified threshold, could potentially result in a number of both on- and off-site fatalities.

List 2 is a longer list of potentially hazardous substances which are commonly found in Canada, both at facilities and in transportation situations. Any release of a List 2 substance, at or above the specified threshold, could result in on-site fatalities and off-site injuries. This includes the substances of List 1, in amounts smaller than the large quantities that merit the top priority of List 1.

List 3 comprises other hazardous substances which are frequently encountered in Canada but present smaller acute risks than those in Lists 1 and 2, and are less likely to cause or be involved in a major accident. They may present environmental or long-term risks.

The Lists give the name of the substance, the usual physical state, Chemical Abstracts Service (CAS) numbers, product identification number / United Nations number (PIN/UN), transport of dangerous goods (TDG) class and division numbers, and a threshold quantity.

The threshold quantities were based on the expert opinion of members of MIACC Working Group 1.

Key factors considered in the compilation of MIACC Lists 1 and 2 were:

  • the physical and chemical properties of the substance;
  • the physical and chemical properties of the decomposition or combustion products; and,
  • the historical involvement of the substance in industrial accidents (primarily its inclusion on the Environment Canada Spills List).

The MIACC Lists of Hazardous Substances were developed by members of MIACC who had expertise in the areas of toxicology, health and safety, emergency response, and enforcement, as the basis for identifying and ranking sites at which handling of hazardous substances takes place from the perspective of public safety risk.

The process involved review of existing lists of hazardous substances. These included the following Canadian Lists: Transportation of Dangerous Goods Regulations, Schedule XII, Environment Canada's Lists of Spilled Chemicals, the Montréal Urban Community's List of Dangerous Substances, the substances listed in the regulation promulgated under the Pest Control Products Act, and the Workplace Hazardous Materials Information System Lists. Other lists reviewed included the U.S. Environmental Protection Agency Superfund Amendments and Re-Authorization Act, Extremely Hazardous Substance List and the Toxic Substances Control Act (TSCA) Inventory, the U.S. Occupational Safety and Health (OSHA 1910.119) List, the International Labour Office Lists of Recommendations for Process Hazards Management of Substances with Catastrophic Potential, the List of Substances from the Netherlands Organization of Applied Scientific Research (TNO) Guide to Hazardous Industrial Activities, and the Seveso I Directive Annex III. Criteria for inclusion in the MIACC Lists were developed considering those used in the creation of the above lists along with other Canadian experience. Hazardous substances not produced or allowed to be imported into Canada at the time were eliminated from the MIACC Lists.

3.2.1. MIACC List 1

MIACC List 1 contains 33 hazardous substances. These substances represented at the time, the substances that were involved in the highest number of accidents in Canada. An accident involving a List 1 substance and quantity could potentially result in a number of on- and off-site fatalities.

3.2.2. MIACC List 2

MIACC List 2 contains 212 hazardous substances. These substances are a combination of MIACC List 1 (at lower thresholds), Extremely Hazardous Substances listed under Section 302 of the EPCRA (SARA Title III) and hazardous substances listed under SEVESO I Directive. Hazardous substances from SARA Title III and SEVESO I were retained if they were listed on the Domestic Substances List (DSL)6.

The threshold quantities in List 2 were based on the quantities set in SARA Title III, SEVESO I and the expert opinion of members of MIACC Working Group 1. The release of these substances at the quantities specified could result in on-site fatalities and off-site injuries.

3.2.3. MIACC List 3

MIACC List 3 contains 68 hazardous substances. These substances were identified as environmentally hazardous substances.

3.3. List of Hazardous Substances from CRAIM

  • Table 4 presents the List of Toxic Substances identified in the CRAIM List (CRAIM Class D).7
  • Table 5 presents the List of Flammable Substances identified in the CRAIM List (CRAIM Class C).8
  • Table 6 presents the List of Explosive Substances identified in the CRAIM List (CRAIM Class E).9
  • Table 7 presents the List of Miscellaneous Substances identified in the CRAIM List (CRAIM Class F).9
Table 4 - Toxic Substances identified in the CRAIM List
CAS NumberChemical NameThreshold Set by Expert Opinion (Tonnes)
107-07-32-chloroethanol1.00
107-05-1Allyl chloride0.45
630-08-0Carbon monoxide10.00
76-06-2Chloropicrin [trichloronitromethane]0.22
7790-94-5Chlorosulfonic acid [chlorosulphonic acid]1.00
506-68-3Cyanogen bromide1.00
10035-10-6Hydrobromic acid [hydrogen bromide]2.25
463-51-4Ketene0.05
7439-97-6Mercury1.00
78-85-3Methacrolein [methacrylaldehyde]0.45
30674-80-7Methacryloyloxyethyl isocyanate0.05
74-83-9Methyl bromide1.15
74-88-4Methyl iodide3.40
78-94-4Methyl vinyl ketone0.05
10102-44-0Nitrogen dioxide0.11
20816-12-0Osmium tetroxide0.05
108-95-2Phenol10.00
7803-52-3Stibine0.22
78-00-2Tetraethyl lead1.00
7719-09-7Thionyl chloride0.11
7616-94-6Perchloryl fluoride [Trioxychlorofluoride]2.25


Table 5 - Flammable Substances Identified in the CRAIM List
CAS NumberChemical NameThreshold Set by Expert Opinion (Tonnes)
107-06-21,2-Dichloroethane [ethylene dichloride]50.00
75-64-92-methyl-2-propanamine [tert-butylamine]10.00
71-43-2Benzene10.00
110-82-7Cyclohexane50.00
75-18-3Dimethyl sulphide10.00
100-41-4Ethylbenzene50.00
86290-81-5Gasoline (motor fuel)50.00
8006-14-2Natural gas4.50
8030-30-6Naphtha50.00
108-88-3Toluene50.00
1330-20-7Xylenes50.00


Table 6 - Explosive Substances Identified in the CRAIM List
CAS NumberChemical NameThreshold Set by Expert Opinion (Tonnes)
* Removed from the list
7775-09-9Sodium chlorate10.00
 Explosives (Class 1.1)* 
7790-98-9Ammonium perchlorate3.40
7722-84-1Hydrogen peroxide (conc 52% or greater)3.40


Table 7 - Miscellaneous Substances Identified in the CRAIM List
CAS NumberChemical NameThreshold Set by Expert Opinion (Tonnes)
7723-14-0Phosphorus, white1.00



  • 5 NFPA, Fire Protection Guide on Hazardous Material , 1984 , 8th Edition, Quincy MA., U.S.A.
  • 6 Part II of the Canada Gazette, May 4, 1994.
  • 7 CRAIM 2001, Guide de gestion des risques d'accidents industriels majeurs à l'intention des municipalités et de l'industrie, p. 118, Conseil régional pour la réduction des accidents industriels majeurs, Montréal, 2001.
  • 8 CRAIM 2001, Guide de gestion des risques d'accidents industriels majeurs à l'intention des municipalités et de l'industrie, p. 119 - 120, Conseil régional pour la réduction des accidents industriels majeurs, Montréal, 2001.
  • 9 CRAIM 2001, Guide de gestion des risques d'accidents industriels majeurs à l'intention des municipalités et de l'industrie, p. 120, Conseil régional pour la réduction des accidents industriels majeurs, Montréal, 2001.
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