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ARCHIVED - Implementation Guidelines for Part 8 of the Canadian Environmental Protection Act, 1999 – Environmental Emergency Plans

Appendix 5 Calculation Of Substance Amount

  1. Quantity in a container
  2. Quantity of a substance in a mixture
    1. Other hazardous substances
    2. Flammables

The threshold quantity for each regulated substance is listed in Appendix 4 of these Implementation Guidelines. You should determine whether the maximum quantity of each substance used or stored at the place is greater than the threshold quantity listed. If it is, you must comply with the Environmental Emergency Regulations for that substance.

Quantity in a container

To determine if you have the threshold quantity of a regulated substance in a container involved in a single process, you need to consider the maximum quantity in that container at any one time. Base your decision on the actual maximum quantity that you may have in the container. Your maximum quantity may be more than your normal operating maximum quantity. For example, if you may use a container for extra storage, the maximum quantity should be based on the quantity that might be stored.

"At any time during a calendar year" means you need to consider the largest quantity that you ever have in the container. If you fill a tank with 20 tonnes and immediately begin using the substance and depleting the contents, your maximum is 20 tonnes.

If you fill the container four times a year, your maximum is still 20 tonnes. Throughput is not considered, because the Regulations are concerned about the maximum quantity you could release in a single event.

Quantity of a substance in a mixture

Other hazardous substances

If you have hazardous substances listed in Part 2 of Appendix 4 within a mixture and their concentration is less than the listed concentration, you do not need to consider them at all.

If one of these substances is in a mixture at a concentration above its listed concentration, you must determine the weight of the substance in the solution and use that to calculate the quantity present. If that quantity is greater than the threshold, the process is covered. For example, aqueous ammonia is covered at concentrations above 20 percent, with a threshold quantity of 9.1 tonnes. If the solution is 25 percent ammonia, you would need 36.4 tonnes of the solution to meet the threshold quantity; if the solution is 44 percent ammonia, you would need 20.7 tonnes to meet the threshold quantity (quantity of mixture x percentage of regulated substance = quantity of regulated substance).

If the concentration is less than the concentration identified in the list, you need not consider the quantity in your threshold determination. If the concentration in a mixture is above the listed concentration, you must calculate the weight of the regulated substance in the mixture and use that weight to determine whether a threshold quantity is present. However, if you can measure or estimate (and document) the partial pressure of the regulated substance in the mixture to be less than 10 mmHg, you do not need to consider the mixture.

If the substance, at or above the specified concentration, is stored or used in amounts equal to or exceeding the threshold quantity and is held in a container with a capacity greater than that of the listed quantity, the preparation and implementation of an environmental emergency plan are required.


Flammable mixtures are subject to these requirements only if there is a regulated substance in the mixture above 1 percent and the entire mixture meets the Transportation of Dangerous Goods Act criteria for flash point and boiling point. If the mixture meets both of these criteria, you must use the weight of the entire mixture (not just the listed substance) to determine if you exceed the threshold quantity. Substances meeting the Transportation of Dangerous Goods Act criteria will rapidly or completely vaporize at atmospheric pressure and normal ambient temperature or are easily dispersed in air and will burn readily. This includes any liquid or gaseous material that is liquid while under pressure and that has a flash point below 23°C and a boiling point below 35°C. These are materials that, if released in an emergency, will pose a significant risk to human life, health or the environment.

If the above criteria are met, an environmental emergency plan is required under the Environmental Emergency Regulations. However, it should be noted that for complex flammable mixtures, Environment Canada requires only the identification of the mixture's main regulated component (e.g., a mixture containing substance x) when filing the first notice identifying the substance and place.

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