Skip booklet index and go to page content

Process for Proposing and Considering Changes to the National Pollutant Release Inventory

3. Considerations for Assessing Proposed Changes to the NPRI

3.1 Decision Factors for the Addition and Deletion of Substances

The decision factors outlined in this section help to determine if the NPRI is the appropriate vehicle to collect the information sought by the change proposal and whether the change is warranted. As written, they apply to additions and deletions of substances. However, the same concepts apply to the consideration of other types of changes to the reporting requirements, where appropriate. Along with the decision factors, the additional considerations (see section 3.3) should also be evaluated.

1. Does the substance meet all of the NPRI criteria, that is:

  1. Is the substance manufactured, processed or otherwise used (MPO) by facilities in Canada?1
  2. Is the substance of health and/or environmental concern?
  3. Is the substance released to the Canadian environment or disposed2 of by facilities, and do facilities contribute significant releases of the substance?
  4. Is the substance present in the Canadian environment?

The first two criteria are intended to be absolute, in the sense that a substance must be MPO by facilities in Canada, and be of health and/or environmental concern, to be on or added to the NPRI. If these criteria are not satisfied for a substance being proposed to the NPRI it should not be added, and if they are not satisfied for a substance currently on the NPRI, it should be deleted.

For the third criteria, there are various ways in which 'significant' can be characterized. The concept relates not only to the proportionate quantity of a substance released by facilities relative to other sources of release of that substance, but also to the absolute quantity in terms of potential for health or environmental impacts from the releases. In other words, even if facilities do not account for a major proportion of total releases, the absolute magnitude of facility releases may nonetheless be significant in the context of environmental/human health impacts depending on such factors as location, timing, concentration, and the potential environmental or health risk associated with the substance.

The fourth criteria indicates that there must be reasonable expectation that a substance is present and of concern as a result (at least in part) of being or potentially being released into the Canadian environment in order for it be added to or retained on the NPRI. In cases of naturally-occurring substances, the contribution of facility releases to environmental presence will be acknowledged in the context of available information on background levels.

2. Does inclusion of the substance support one or more of the objectives of NPRI?

The following are the objectives of the NPRI:

  • To improve public understanding
  • To identify priorities for action
  • To encourage voluntary action to reduce releases
  • To allow tracking of progress in reducing releases (including successful reductions)
  • To support targeted regulatory initiatives
  • To support development of other pollutant release inventories, such as the Air Pollutant Emissions Inventory, and related international reporting obligations, where appropriate.

In looking at whether the change would meet the objectives of the NPRI, the additional considerations below in section 3.3, such as value, costs and the ability of facilities to obtain and report data of meaningful quality, should also be taken into account.

3. Is the substance reported elsewhere in Canada? If it is reported elsewhere, is there nonetheless additional value in reporting the information through the NPRI?

If a substance is reported or regulated elsewhere, the benefit of adding or deleting it from the NPRI would be evaluated, taking into account whether doing so would fill information needs (described by the proponent) and whether the NPRI is an appropriate vehicle to collect the information. For example, consideration would be given to whether:

  • The existing information on the substance is as publicly available as it would be through the NPRI (keeping in mind the importance of existing confidentiality protections where appropriate);
  • The existing information is available at the facility level, as it would be through the NPRI;
  • The existing information is comparable in terms of comprehensiveness that would be captured by the NPRI; and
  • The quality and type of existing data is comparable to what NPRI would collect (e.g., absolute quantities versus concentration).

If a substance reported elsewhere in Canada is deemed appropriate to include or retain in the NPRI, to the greatest extent possible, efforts will be made to consolidate the reporting requirements to effectively and efficiently meet multiple data needs (assuming compatibility of data requirements, confidentiality, timing, etc.).

4. Is the substance already on the NPRI in some form? If it is already on the NPRI in some form, is there nonetheless additional value in including it in another form?

When considering adding a substance in another form (e.g., tetraethyl lead as a separate listing from lead and its compounds), efforts should be made to avoid the potential for double-counting. In other words, where possible, the listing of a compound as both an individual substance and included as part of an aggregate category should be avoided. In any case, a clear definition for a listed substance is very important to minimize potential for double-counting and confusion among reporting facilities and data users.

3.2 Categories and Criteria for Threshold selection (including Alternate Thresholds)

Once a substance has met the decision factors for its inclusion on the NPRI (see section 3.1), one must then look at the overall NPRI criteria describing what facilities are subject to the Canada Gazette reporting requirement notice3 to ascertain whether these criteria impact achievement of the data objectives. Specifically, this includes looking at the: 

  • The 20,000 hour employee threshold,
  • The list of specified activities for which reporting to the NPRI is required, irrespective of employee-hour count.

If either of these present a barrier to collecting the data being sought by the proponent, then the proponent should explain how, and may opt to propose the exclusion/exemption of these criteria (with clear justification) for the threshold at hand. The proponent is encouraged to look at current NPRI reporting requirements (e.g., Part 1-Part 5)4 for examples of threshold design.

Following this, analysis must be undertaken to determine and justify an appropriate reporting threshold type and quantitative level. Unless otherwise justified, the standard default reporting threshold of the NPRI is 10 tonnes MPO (at a concentration of 1% or more except for by-products), and is a good starting point for this analysis. However, to best meet the data objectives of the NPRI and the change being proposed, the proponent can propose an alternate threshold with justification as to why this would better achieve the objectives.

The following paragraphs outline the options (both type and quantitative level) for thresholds. Feasibility factors to consider such as various costs, benefits, and other considerations for determining what threshold is appropriate, are discussed in greater detail in section 3.3.

3.2.1 Selection of Threshold Type

As mentioned above, once a substance has met the decision factors for its inclusion on the NPRI (see section 3.1), analysis must be undertaken to determine and justify an appropriate reporting threshold type and quantitative level.  The three different types of thresholds currently used under the NPRI are described in the following sections.

Manufacture, Process and Other Use (MPO) Thresholds:

The MPO threshold is the standard default type of threshold for NPRI substances.  Once the 20 000-hour employee threshold is met or specified activities take place at the facility, facilities would consider the quantity of the substance MPO at a concentration at or above a specified concentration threshold  (and by-products and mine tailings at any concentration) to determine if they need to report to the NPRI.

An MPO reporting threshold should be used when the substance of concern is a commercial chemical or product, or a contaminant in a commercial chemical and/or product. More information on levels (quantities and concentrations) for this type of threshold are discussed below in section 3.2.2.

Release-based Thresholds:

A release threshold (usually defined as an annual sum quantity released, or loading) can be used when the substance of concern is primarily incidentally manufactured and MPO data is difficult to obtain, or release data is available. For example, when a substance is a combustion product, or is not a commercial chemical or product.

While incidental manufacture is considered to be a form of manufacture in NPRI, in cases where it is difficult for facilities to estimate the quantity of the substance that is incidentally manufactured, an MPO threshold may not be appropriate. On the other hand, information on these types of substances may be more readily accessible in the form of measurements or estimations (e.g., based on emission factors) of releases to the environment (or disposals or transfers), and in these cases a reporting threshold based on this release (or disposal or transfer) information can be more appropriate. Care should be taken when considering thresholds that rely on estimation methods such as emission factors, as these are not without uncertainty, tend to evolve over time and therefore may need more frequent updating.

Activity-based Thresholds:

An activity-based threshold may be considered where the types of facilities, or activities, or processes associated with the substance releases (and/or impacts of concern) are well defined, and where it may be difficult to establish an appropriate MPO or release-based threshold. This type of threshold would typically require all facilities of a specified type, or where specified activities take place, to report for a substance or substances regardless of the quantity of substance MPO or released. In some cases it may be useful to also include a minimum limit to preclude reporting from facilities who handle very small quantities. The 20 000-hour employee threshold can be included or removed for this type of threshold depending on the data objectives.

This particular type of threshold has been used for dioxins/furans and hexacholorobenzene (HCB). Activities that were identified under the Canada-wide Standards as sources of these substances, as well as “titanium dioxide pigment production using chloride process”, are the activities that are listed in the NPRI notice and require reporting for these substances.  Further details on this example can be found in the NPRI Part 3 reporting requirements.

3.2.2 Selection of Quantitative Threshold Levels

In combination with choosing a threshold type (see section 3.2.1) for substances that have met the criteria for inclusion in the NPRI, the change proposal must also justify a quantitative level for the threshold. Many substances have unique contexts (e.g., chemical properties, quantities MPO, sources of releases, and level and types of environmental and/or health impacts), therefore the selection of quantitative aspects of their NPRI thresholds must account for the context at hand. Keeping in mind the data objectives of the change proposal, there are two ways in which the quantitative aspects of a threshold  are commonly selected and justified:

  1. Using a coverage-based analysis
  2. Using a level that aligns with appropriate science-based impact thresholds, and/or with other compatible reporting levels as appropriate and justified.

The approach a proponent chooses to justify quantitative aspects of the threshold is made based on context (e.g., data objectives of the change proposal and availability of information, etc.) and a rationale statement should be included in the proposal.

In a  coverage-based approach, a proponent can leverage various data (e.g., facility production or release data, among others) if available to calculate coverage rates expected at various threshold levels, to identify a level at which an appropriate balance of value (e.g., achieving satisfactory data) and costs/other feasibility factors (discussed below in section 3.3) is judged to be reached. Ideally, the optimal coverage rate should be established using the proportion of releases from industrial sources that would be reported to the NPRI at different threshold levels. However, in cases where this type of analysis is not possible (e.g., limited availability of data), the proportion of quantities used (e.g., MPO) or the number of facilities captured may be considered. ECCC will try to provide this coverage analysis within consultation documents to promote meaningful consultation, where that data may not be available to the proponent or stakeholders. In cases where the data used by ECCC are not publicly available, a summary will be provided, if possible.

In certain cases where context and proponent data objectives allow and align, it may be more appropriate to streamline threshold levels with other reporting activities (e.g., past or current, intermittent or ongoing, for business or environmental programs). This option could be used when a coverage-based approach cannot be (e.g., information to calculate potential coverage rates is limited or not available, and data objectives allow), and/or could be used strategically to mitigate reporting burden for compatible data (e.g., leverage existing methodologies; measure and report once to meet multiple data/program needs). In this case, a proponent must include a rationale statement behind the threshold alignment. Threshold levels may be based on thresholds used in CEPA section 71 notices for the substance and/or risk-assessment information, and/or risk management instruments for the substance. For example, a reporting threshold already used by a Pollution Prevention (P2) Planning requirement for the substance might be strategic to use for the NPRI if it eases reporting burden, creates efficiency and meets the data objectives of the proposal and the NPRI. Leveraging thresholds from risk assessments or risk management instruments may be appropriate  if they are risk-based, suitable to NPRI reporting and achieve the data needs of the proponent. Harmonizing reporting requirements with other Pollutant Release and Transfer Registersinternationally may also be of value if the threshold level is also in the Canadian interest and meets the stated objectives without undue burden. As with the coverage-based approach above, the goal is to identify a threshold level at which an appropriate balance of value (e.g., achieving satisfactory data) and costs/other feasibility factors (discussed below in section 3.3) is judged to be reached.

To minimize complexity, the threshold level being proposed should be chosen from a limited number of defined threshold values (e.g., 5 kg, 50 kg, 100 kg, 1 000 kg, 10 tonnes) with supporting justification.

As the threshold quantity is chosen, the (default) 1% concentration by weight exemption should be reviewed, and modified or excluded if it is expected to present a barrier to reporting coverage. Similarly, if there is a more appropriate value (e.g., risk-based and/or efficiency-based such as alignment with other reporting activities like safety data sheets), the proponent can propose this with justification as to why this would better achieve the data objectives.

3.3 Additional Considerations for Additions, Deletions, Alternate Thresholds, or Other Types of Changes

The decision factors outlined in section 3.1, as written, apply to additions and deletions of substances. However, the same concepts apply to the consideration of other types of changes to the reporting requirements, where appropriate. In addition to considering the appropriate decision factors, the following points should also be considered for additions, deletions, alternate thresholds, and other types of changes. 

3.3.1 Value versus Cost

A change proposal should discuss the value versus the cost of the change being proposed. The drivers behind NPRI change proposals are outlined above (see section 1.0), and so value can be demonstrated when those drivers are fulfilled and information gaps are reduced enough to obtain data that meets the stated objective(s). Key factors to keep in mind when considering the value of a proposed change include whether there is value in requiring the on-going reporting of additional information (e.g., does the change support the drivers listed above)? Are there missing sectors or facilities likely to contribute significant releases that would help fill a gap in the NPRI? Will the data received be of satisfactory quality to meet identified objectives?  

Other key factors to account for and justify are the value of the information versus the cost of obtaining it (e.g., technology/capital costs, time, other resources, other indirect/downstream consequences) and making it available through the NPRI. Excessive cost can in some cases be judged to outweigh the value of certain data/levels of detail and thus influence the outcome of the change proposal. Efforts will be made to implement reasonable measures to reduce costs to reporting facilities and government, without compromising the NPRI.

In the case of proposed deletions, a proponent is expected to justify the low value of the data (currently  or known/forecast as substance release patterns change) and/or any costs (or cost-savings) associated with the deletion.

3.3.2 Capability of Facilities to Provide the Required Information

Another factor to consider in the change proposal is the capability of reporting facilities to provide the required information (e.g., existence of estimation methods, analytical methodology, or monitoring data) at a reasonable level of quality. Capability refers to the state of knowledge about the source in question. Facilities are required (by CEPA) to report information that is in their possession or to which they may be reasonably expected to have access. Capability at a reasonable level of quality is not static; it can be improved though method development, testing and guidance.

It should not be assumed that facilities can easily report high quality data simply because they already have to determine if they meet a reporting threshold. Typically less robust methodologies are used to test if emissions exceed reporting thresholds. The resulting information may not be of adequate quality for public reporting, and could require substantially more work and cost to ensure that reported data is of sufficient quality (e.g meaning, the data enables an accurate picture of releases and transfers, and allows for appropriate use and interpretation as per the stated objectives). Where data value is high, and cost for method development is also high, ECCC will aim to work in partnership with reporters to develop acceptable reporting methodologies/mechanisms, so that a lack of acceptable estimation methods is not a barrier to reporting for a particular substance or sector.

It is very important to provide a clear definition for a substance listed on the NPRI, to minimize potential for double-counting and confusion among reporting facilities and data users. Where a CAS Registry Number exists for an individual substance or a defined group of substances, it must be included as this is the typical way for a facility to identify whether this substance is MPO and in what quantities. In the cases of aggregate or grouped substance listings, a single CAS Registry Number may not exist. In those cases, the substance may be defined by listing the individual substances that comprise the grouping with their CAS Registry Numbers (e.g., for “nonylphenol and its ethoxylates”), by defining the substance grouping in as much detail as possible and indicating which specific individual compounds are not included (e.g., for “lead (and its compounds)”), or by defining the substance grouping otherwise where a list of CAS Registry Numbers is not possible to define (e.g., “particulate matter < 2.5 microns”).

3.3.3 Alternate Means for Reducing Data Gaps

If a change is being proposed to address a (perceived) data gap, the proponent should consider the full context of why the gap exists in the first place before proposing (and justifying) a change. The explanation behind the (perceived) data gap may lead a proponent to consider alternative methods to reduce a data gap (e.g., compliance promotion if appropriate), to alter the type of change proposed, or negate the perceived need for a change proposal altogether. For example, the fact that a substance is consistently unreported is not necessarily grounds for deletion. There could be a number of reasons for this other than the current threshold level, including reporting of data under several different sector codes, communication issues about the requirement to report, reporters switching to an alternate estimation method or substance or technology, or facility closures or shut-down periods, etc. In these cases and others, a change to the NPRI may or may not be warranted, and other options for reducing data gaps may also be (more) appropriate.

3.3.4 Coverage and Comprehensiveness

The NPRI should aim to present as complete and comprehensive a picture as possible of the release sources of NPRI substances.  As discussed in section 3.2.2, ideally, the proportion of releases captured should be optimized rather than the proportion of quantities used or the number of facilities captured. In addition, it may be appropriate to consider other sources of releases (e.g., from natural background, residential, or transportation, etc.) because some substances may come largely from non-facility-based sources which are not targeted for capture in the NPRI. 

All facilities meeting the reporting conditions should report their releases, and sector specific reporting requirements should only be put in place if there is a strong justification. Opportunities for simplicity should be sought, as overly complex requirements may negatively impact the NPRI (e.g., potentially discourage reporters and users). For example, it may be reasonable to exempt certain types of facilities from reporting if determining the quantity of an NPRI substance used or released may be unusually difficult or cost prohibitive. An exemption could also be appropriate when reporting would be an unreasonable burden for a particular type of facility or if it is unlikely that a particular type of facility would meet the reporting conditions. In addition, if the information is already being collected through another program or could be better obtained by means other than reporting to the NPRI, the information could subsequently be incorporated into the NPRI data base in a compatible form.

3.3.5 Other data gathering planned

If there is other data gathering planned or ongoing within ECCC for this substance or in other jurisdictions (e.g., provincial or international programs), there may be benefits in waiting for this information prior to making changes to the NPRI. For example, other data gathering could better inform substance definition, analytical methodologies, or reporting needs/impacts. The proposed change could be revisited when the data becomes available. Whether to wait for other data gathering to consider or implement a change to the NPRI may depend on a balance of factors such as the timing of data availability and data needs, potential impacts of the substance, and the expected outcomes of the other data gathering.


Footnote 1

Note that MPO includes both intentional and unintentional manufacture and/or production (i.e. co-incidentally produced, or produced as a by-product)

Return to footnote 1 

Footnote 2

A disposal of a substance is defined as its:

  1. final disposal to landfill, land application or underground injection, either on-site or off-site;
  2. transfer off-site for storage or treatment prior to final disposal; or
  3. movement into an area where tailings or waste rock are discarded or stored, and further managed to reduce or prevent releases to air, water or land, either on-site or off-site.

Return to footnote 2 

Footnote 3

More information available at: Canada Gazette notices.

Return to footnote 3 

Footnote 4

More information available at: Canada Gazette notices and Summary of NPRI reporting requirements.

Return to footnote 4 

Date modified: