On March 5, 2026, Environment and Climate Change Canada and Health Canada jointly released the Risk Assessment Framework for Manufactured Nanomaterials under the Canadian Environmental Protection Act (CEPA), outlining the framework for nanomaterial risk assessment and key considerations.
Background
Nanotechnology has the potential to be applied across a wide range of fields and scenarios. Compared with traditional chemical substances, nanomaterials may exhibit different behavioral characteristics regarding potential risks to human health and the environment. Therefore, nanomaterials require assessment approaches distinct from those for conventional chemicals. On June 17, 2022, Canada released the draft framework, which underwent a 60-day public comment period.
Key Points
1. Definition of Nanomaterials (Applicable under CEPA)
- At least one external dimension is at or within the nanoscale (1-100 nm), or has internal or surface structures at the nanoscale; or
- Smaller or larger than the nanoscale in all dimensions, but exhibits one or more nanoscale properties/phenomena
Specific Thresholds:
- By number: ≥10% of primary particles have at least one internal or external dimension within the nanoscale
- By mass (if number distribution data unavailable): ≥1% of primary particles are within the nanoscale
- Agglomerates and aggregates (regardless of external size) are also considered nanomaterials if their constituent particles meet the definition
2. Basic Principles (Building on Existing Regulatory Frameworks)
Following OECD recommendations, the framework adapts existing chemical substance regulatory frameworks rather than establishing entirely new nanomaterial-specific regulations; nanomaterial risk assessment must consider their unique physicochemical properties (size, shape, surface chemistry, etc.); conservative yet realistic assumptions are applied when data is uncertain.
3. Legislative and Regulatory Framework for Existing and New Nanomaterials
Canada utilizes existing legislative and regulatory frameworks under the Canadian Environmental Protection Act (CEPA) for bulk chemicals and polymers to assess and manage potential risks of nanomaterials (NMs) to human health and the environment. While these frameworks apply in principle to nanomaterials, adjustments are sometimes necessary to account for nanomaterial-specific characteristics (e.g., physicochemical properties, lifecycle/transformation products).
- For existing nanomaterials, Environment Canada has collected data to establish an inventory of nanomaterials in commercial circulation in Canada and conducted research on approaches for nanoscale substances on the Domestic Substances List (DSL).
- For new nanomaterials, importers or manufacturers must provide relevant information under the New Substances Notification Regulations (NSNR). Environment Canada and Health Canada use this information to assess whether nanomaterials meet the criteria specified in Section 64 of CEPA.
4. Risk Assessment Methodology for Chemicals and Polymers
Risk assessment is the process of evaluating the likelihood of adverse consequences from substances, considering both hazard and exposure:
- Hazard: The inherent ability of a substance to cause adverse effects
- Exposure: The concentration or amount of a substance reaching an organism, system, or population with specific intensity, frequency, and duration
Quantitative risk characterization uses Risk Quotient (RQ) and Margin of Exposure (MOE):
- RQ (Risk Quotient) = Predicted Environmental Concentration (PEC) / Predicted No-Effect Concentration (PNEC)
- RQ ≥ 1: Potential environmental hazard
- RQ < 1: Unlikely to cause environmental harm
- MOE (Margin of Exposure) = Critical Effect Level / Exposure Level
- Used for human health risk assessment
- Derived MOE less than target MOE indicates potential health hazard
5. Application of Uncertainty, Weight of Evidence, and Precautionary Measures
Risk assessment under CEPA relies on Weight of Evidence (WoE) and the precautionary principle to address uncertainty:
- Weight of Evidence (WoE): A decision-making approach involving consideration of multiple information sources and lines of evidence
- Precautionary Principle: Using conservative yet realistic assumptions to account for uncertainty
- Degree of precaution is proportional to the degree of uncertainty
The framework emphasizes that nanomaterial risk assessment is a science-driven, comprehensive decision-making process that integrates hazard characterization with exposure information, applying Weight of Evidence methods and the precautionary principle to ultimately determine whether substances meet the "toxic" criteria under Section 64 of CEPA, thereby identifying whether risk management measures are required.
Further Information
