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ARCHIVED - Guidance Manual for the Risk Evaluation Framework for Sections 199 and 200 of CEPA 1999 : Decisions on Environmental Emergency Plans

4. Appendices

4.1. Section 199 of CEPA, 1999

Section 199 of Canadian Environmental Protection Act, 1999 states, in part:

  1. The Minister may at any time publish in the Canada Gazette, and in any other manner that the Minister considers appropriate, a notice requiring any person or class of persons described in the notice to prepare and implement an environmental emergency plan respecting the prevention of, preparedness for, response to or recovery from an environmental emergency in respect of

    1. a substance or group of substances on the List of Toxic Substances in Schedule 1; or

    2. a substance or group of substances in relation to which there has been published in the Canada Gazette
      1. a statement of the Ministers under paragraph 77(6)(b) indicating that the measure that they propose to take, as confirmed or amended, is a recommendation that the substance be added to the List of Toxic Substances in Schedule 1, or
      2. a copy of an order proposed to be made under subsection 90(1).

  2. The notice shall specify

    1. the substance or group of substances in relation to which the plan is to be prepared;

    2. the period within which the plan is to be prepared;

    3. the period within which the plan is to be implemented; and

    4. any other matter that the Minister considers necessary.

4.2. Section 200 of CEPA, 1999

Section 200 of CEPA, 1999 states:

  1. The Governor in Council may, on the recommendation of the Minister and after the Committee is given an opportunity to provide its advice to the Minister under Section 6, make regulations

    1. establishing a list of substances that, if they enter the environment as a result of an environmental emergency,

      1. have or may have an immediate or long-term harmful effect on the environment or its biological diversity,
      2. constitute or may constitute a danger to the environment on which human life depends, or
      3. constitute or may constitute a danger in Canada to human life or health;

    2. prescribing, in respect of a substance on the list established under paragraph (a), a minimum quantity;

    3. respecting the identification of the places in Canada where a substance referred to in paragraph (a), in any quantity or in the quantity prescribed for that substance under paragraph (b), is located and requiring notification to the Minister of those places;

    4. respecting the prevention of, preparedness for, response to and recovery from an environmental emergency in respect of a substance;

    5. respecting the notification and reporting of an environmental emergency;

    6. respecting the notification and reporting of the measures taken
      1. to prevent the environmental emergency, or
      2. to repair, reduce or mitigate any negative effects on the environment or human life or health that result from the environmental emergency or that may reasonably be expected to result from it;

    7. respecting the implementation of international agreements entered into by Canada in relation to environmental emergencies; and

    8. respecting any other matter necessary for the purposes of this part.

  2. The Governor in Council shall not make a regulation under subsection (1) in respect of a matter if, by order, the Governor in Council states that it is of the opinion that

    1. the matter is regulated by or under any other Act of Parliament that contains provisions that are similar in effect to sections 194 to 205; and

    2. that Act or any regulation made under that Act provides sufficient protection to human health and the environment or its biological diversity.

4.3. Details on Human Inhalation Toxicity Measurements

4.3.1. AEGL

The U.S. EPA has shifted from using LC50 values to Acute Exposure Guideline Levels (AEGL) in determining relative hazards of chemicals in emergency situations. The primary purpose of the AEGL program is to develop guideline levels for once-in-a-lifetime short-term exposures to airborne concentrations of acutely toxic, high priority chemicals. A principle objective of the program is to develop scientifically credible acute (short-term) once-in-a-lifetime exposure guidelines within the constraints of data availability, resources and time. AEGLs represent threshold exposure limits for the general public and are applicable to emergency exposure periods ranging from 10 minutes to 8 hours. It is believed that exposure levels are applicable to the general public, including susceptible groups, such as infants, children, the elderly, persons with asthma, and those with other illnesses. However, it is recognised that individuals, subject to unique or idiosyncratic responses, could experience the effects described at concentrations below the corresponding AEGL (National Research Council, 2001).

For each chemical exposure levels are developed for a minimum of five exposure periods (10 minutes, 30 minutes, 1 hour, 4 hours, 8 hours). In addition, for each exposure period, three levels or "tiers" representing different severity of toxic effects are established as follows:

  • AEGL-1 is the airborne concentration (expressed as ppm or mg/m3 of air) of a substance above which it is predicted that the general population, including susceptible individuals, could experience notable discomfort.
  • AEGL-2 is the airborne concentration (expressed as ppm or mg/m3 of air) of a substance above which it is predicted that the general population, including susceptible individuals, could experience irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape.
  • AEGL-3 is the airborne concentration (expressed as ppm or mg/m3 of air) of a substance above which it is predicted that the general population, including susceptible individuals, could experience life-threatening health effects or death.

The U.S. EPA envisions that AEGLs will be applied in the areas of emergency preparedness and response, chemical accident prevention in transportation and fixed facilities, worker safety, contaminated site remediation, destruction of chemical warfare agents, and chemical terrorism counter activities. The development of AEGLs has been slow due to the amount of work it takes to generate a final value, to date there are AEGLs for only 26 chemicals. In the REF the AEGL 2, 1-hour exposure is used, as it should correspond with an ERPG 2 value (see below).

4.3.2. ERPG

The U.S. Department of Energy Chemical Safety Program uses Emergency Response Planning Guidelines (ERPGs) to assess the threat to humans from chemicals in air (U.S. DOE, 2001). The concentrations given are designed to be a warning of potential health effects, but are not lethal concentrations. There are three levels; one being the lowest is correlated with minor transient effects, while 3 is associated with serious, but non-life threatening effects. Theoretically, an AEGL 1-hour value and a corresponding ERPG value should be the same for a chemical, although in practice there are differences based on the interpretation of data.

  • ERPG-1 The maximum concentration in air below which it is believed nearly all individuals could be exposed for up to one hour without experiencing other than mild transient adverse health effects or perceiving a clearly defined objectionable odor;
  • ERPG-2 The maximum concentration in air below which it is believed nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms that could impair their abilities to take protective action;
  • ERPG-3 The maximum concentration in air below which it is believed nearly all individuals could be exposed for up to one hour without experiencing or developing life-threatening health effects.

The ERPG 2 value was used as the starting point and from there the ranges of chemical concentrations were divided into 5 categories. The value 0.5 ppm was chosen as the lowest concentration as this is the value that the U.S. EPA chose as a criterion for inhalation toxicity to include a chemical on their RMP list, although in that case they used an LC50 4-hour exposure. In the REF the top two scores are multiplied by 5 to increase the importance of this parameter in the overall score.

An AEGL/ERGP 2 concentration that is ≤ 5 ppm is used as a single criterion for requiring an E2 Plan, regardless of other data. It was felt that these compounds could be extremely toxic to humans via inhalation so that any sort of spill involving them is a high-risk situation and thus should have an E2 Plan. In comparison with the U.S. EPA criteria for inclusion on the RMP list (LC50 4-hr exposure) this trigger value is more conservative as it is a non-lethal criterion although it is over a shorter exposure period. This scale is shown in Table 4 below.

4.3.3. OSHA STEL

The U.S. Occupational Safety and Health Administration develop Short Term Exposure Levels (STEL) in cooperation with the U.S. National Institute of Occupational Safety and Health (U.S. Occupational Safety and Health Administration, 1971). These values represent concentrations in air that are of significant hazard to exposed workers over a 15-minute time period, but are not lethal values. They can be inhaled or absorbed through the skin. A STEL is defined by the American Council of Governmental Industrial Hygienists as the concentration to which workers can be exposed continuously for a short period of time (usually 10 or 15 minutes) without suffering from: irritation; chronic or irreversible tissue damage; or narcosis of sufficient degree to increase the likelihood of accidental injury, impair self-rescue or materially reduce work efficiency. A STEL is typically a 10 or 15 minute exposure and is therefore more conservative than an equivalent AEGL 2 or ERPG 2 that are set for a 1 hour exposure, although they are often based on the interpretation of different data.

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