Endocrine Disruptor Assessment Under CLP: Key Challenges and How We Delivered a Robust, Regulator-Ready Outcome

Key Challenges

A global client manufacturing a widely used industrial chemical approached RegSurance to assess whether their substance meets the new ED hazard classes under CLP. They faced four primary challenges:

• No direct OECD test data available for ED ENV endpoints
• Dispersed and inconsistent literature across various sources and study formats
• Ambiguity in interpreting mode of action and adversity under the revised CLP criteria
• Regulatory pressure and customer demand for clarity and timely classification

These challenges required not only scientific expertise but also strategic navigation of complex EU regulatory frameworks.

Methodology Adopted

We applied a structured, science-driven approach grounded in:

• CLP Delegated Regulation (EU) 2023/707 — specifically the criteria for ED HH and ED ENV, Category 1 and 2
• EFSA–ECHA Guidance 2018 on identifying endocrine disruptors
• OECD Conceptual Framework (Levels 2–5) for data relevance and strength
• Systematic weight-of-evidence (WoE) synthesis based on transparency, reliability, and causality

Our approach ensures transparent evidence synthesis in line with EU regulatory mandates—delivering scientifically justified outcomes with regulatory confidence.

Steps Taken

1. Regulatory Criteria Mapping

We identified the precise decision points required under CLP 2023/707, including:

• Evidence of endocrine mode of action (MoA)
• Presence of adverse effects relevant to ED endpoints
• Establishment of a biologically plausible link between MoA and adverse outcome
• Differentiation between Category 1 (known or presumed) and Category 2 (suspected) based on the level of certainty

2. Systematic Literature Review

We conducted a comprehensive, reproducible literature search using:

• PubMed, TOXNET, REACH dossiers, and public assessments
• Inclusion of peer-reviewed studies, regulatory evaluations, and grey literature
• Reliability scoring using Klimisch criteria and ECHA WoE guidance

All findings were logged and evaluated in a structured evidence table.

3. Data Gap Identification and Read-Across

Where direct data was lacking:

• We applied read-across strategies using structurally similar analogues under REACH Annex XI
• Justifications were based on metabolic pathways, MoA relevance, and exposure similarity
• Expert toxicologists reviewed all analogues and bridging arguments

4. Mode of Action and Adversity Assessment

We assessed:

• Hormonal activity and disruption (estrogen, androgen, thyroid, steroidogenesis)
• Adverse effects (e.g., reproductive, developmental, neurological, or ecotoxicological endpoints)
• Biological plausibility of the link between the two, as required under ED criteria

The conclusions were formed using the EFSA–ECHA 2018 weight-of-evidence decision tree.

5. Dossier Development and Conclusion

We delivered a comprehensive ED assessment dossier that included:

• A full weight-of-evidence summary with reliability scoring
• Scientific justification for non-classification under ED HH and ED ENV
• References to relevant EU guidance, literature, and regulatory precedents
• A transparent, traceable methodology suitable for regulatory submission or internal compliance reporting

Final Results and Delivery

Our expert-led approach enabled the client to:

• Avoid ED classification, based on current scientific evidence and regulatory criteria
• Support downstream users with clear, science-backed ED conclusions for SDS updates and risk communication
• Respond confidently to authorities and customers requesting classification status under CLP 2023/707
• Maintain EU market access without triggering unnecessary regulatory actions or restrictions

Outcome: A transparent, regulator-ready dossier—delivered on time, aligned with EU expectations, and grounded in scientific best practice.

Why It Matters for Industry

The introduction of ED hazard classes under CLP is a major regulatory shift. Companies can no longer afford to delay or rely on assumptions.

You need:

• A defensible, science-based assessment methodology
• Clear understanding of regulatory expectations and classification thresholds
• The ability to communicate your position confidently—internally and externally

That’s where RegSurance adds value—by combining scientific depth with regulatory precision.

Need Expert Help With ED Classification?

If you’re unsure whether your substance meets ED criteria—or how to document a justified non-classification—RegSurance can help.

We provide:

• Systematic WoE assessments
• Dossier preparation and classification strategy
• Scientific and regulatory support for REACH, CLP, and SDS updates

Let’s talk. Contact us or visit our website.