Abstract

In recent decades, international frameworks and standards have converged on the concept of human rights due diligence (HRDD) as a central mechanism for responsible corporate behavior, particularly in global value chains characterized by complex, multi-tiered supplier relationships. This article examines how HRDD is articulated and operationalized within the UN Guiding Principles on Business and Human Rights (UNGPs) and four prominent social auditing standards: SA8000:2026, amfori BSCI, ISO 26000, and SMETA/Sedex. Crucially, the analysis situates these frameworks within the emerging European Union regulatory landscape, especially the Corporate Sustainability Due Diligence Directive (CSDDD, Directive 2024/1760) and Corporate Sustainability Reporting Directive (CSRD), which impose legally binding HRDD obligations and disclosure requirements on large corporations operating in or into the EU. The findings show a convergence of principles across voluntary and regulatory regimes and highlight the opportunities and challenges in aligning voluntary standards with evolving EU due diligence laws to improve both compliance and human rights outcomes.

Keywords: human rights due diligence, UNGPs, SA8000, amfori BSCI, SMETA, ISO 26000, EU CSDDD, CSRD

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1. Introduction

Human rights due diligence (HRDD) has emerged as the conceptual and operational core of modern corporate responsibility frameworks. Defined as a systematic, proactive, risk-based process for identifying, preventing, mitigating, and accounting for adverse human rights impacts linked to a company’s activities and business relationships, HRDD reframes social auditing beyond compliance toward impact-oriented risk management centered on rights-holders rather than mere regulatory conformity.

International soft law instruments such as the UN Guiding Principles on Business and Human Rights (UNGPs)establish HRDD as a universal expectation for businesses. Cognizant of the UNGPs, voluntary social auditing standards (e.g., SA8000, amfori BSCI, SMETA) and guidance frameworks (ISO 26000) translate these principles into operational methodologies. At the same time, the European Union’s emerging legislative regime, particularly the Corporate Sustainability Due Diligence Directive (CSDDD) and the Corporate Sustainability Reporting Directive (CSRD), enshrine aspects of HRDD into mandatory legal obligations for companies above specific size and revenue thresholds.

This article comparatively analyses how HRDD is conceptualized and implemented across these voluntary standards and how they align with or can support compliance with EU due diligence legislation.

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2. Conceptual Foundations: Human Rights Due Diligence

2.1 The UN Guiding Principles on Business and Human Rights

The UN Guiding Principles on Business and Human Rights (UNGPs) provide the canonical normative framework that defines the corporate responsibility to respect human rights, including the requirement to carry out HRDD. Under the UNGPs, HRDD is a continuous and proactive process encompassing the identification, assessment, mitigation, and remediation of actual and potential adverse human rights impacts linked to a company’s operations and value chain. The emphasis is on risk to people, not risk to business alone, which fundamentally reshapes the logic of social auditing from compliance checks toward impact management.

The UNGPs stipulate that due diligence should be proportionate to the severity and likelihood of impacts and embedded in company policies, systems, and operational practices. HRDD must include tracking and communicating performance and effectiveness of mitigation measures. This risk-based and people-centric orientation forms the ethical backbone for both voluntary standards and evolving regulatory requirements.

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3. HRDD in Voluntary Social Auditing Standards

3.1 SA8000:2026 — Social Accountability as Due Diligence

SA8000, developed by Social Accountability International, is one of the oldest and most widely recognized social certification standards, grounded in internationally accepted human rights conventions. The latest 2026 revision strengthens its alignment with modern HRDD concepts by emphasizing risk-based management, worker voice, supply chain responsibility, and continuous improvement.

SA8000’s management system requirements require organizations to:

• Establish policies reflecting commitments to labor and human rights.
• Conduct periodic assessments of risks and non-conformances in own operations and supply chains.
• Implement corrective action plans and preventive measures.
• Monitor performance through internal audits, management reviews, and worker consultations.

These elements align with the core steps of HRDD specified in the UNGPs — identify, integrate, act, track, communicate — albeit with a primary focus on labor rights rather than the full human rights spectrum. SA8000 operationalizes HRDD within a verifiable audit and certification framework, which enhances accountability and stakeholder trust.

3.2 amfori BSCI — Supply Chain Due Diligence in Practice

The amfori Business Social Compliance Initiative (BSCI) Code of Conduct is a widely used supply chain monitoring system. Its due diligence process includes:

• Supplier self-assessment and risk profiling based on country and sector contexts.
• Independent third-party audits using standardized protocols.
• Corrective action plans and improvement cycles.
• Engagement with suppliers to build capacity and resolve non-conformances.

Though historically compliance-oriented, amfori BSCI has evolved toward risk-based supplier engagement, with an increasing emphasis on continuous improvement and stakeholder involvement, consistent with HRDD logic. However, the focus remains mainly on labor and social standards, requiring complementary frameworks to cover broader human rights and environmental issues.

3.3 SMETA/Sedex — Ethical Auditing and Transparency

SMETA (Sedex Members Ethical Trade Audit), developed by the Sedex platform, offers a methodology for ethical audits covering four pillars: labor standards, health and safety, environment, and business ethics. SMETA audits are not a standard per se, but they facilitate data sharing and comparability across companies and supply chains, enabling buyers to identify and track human rights risks collaboratively.

SMETA supports HRDD through:

• Systematic audit data collection across suppliers.
• Transparency of results via the Sedex platform.
• A common auditing methodology designed to reduce audit fatigue.

However, audit-centric approaches like SMETA have been critiqued for emphasising conformity over root-cause analysis and for insufficiently integrating stakeholder voices beyond audit checklists — aspects critical to effective HRDD.

3.4 ISO 26000 — HRDD as Strategic Guidance

ISO 26000 is a voluntary guidance standard that positions human rights due diligence within the broader context of social responsibility and ethical governance. Unlike certification standards, ISO 26000 provides principles, core subjects, and integrative guidance rather than auditable requirements.

ISO 26000 emphasizes:

• The need to respect human rights as a foundational principle of social responsibility.
• The importance of stakeholder engagement in identifying and addressing impacts.
• The requirement to address direct and indirect adverse impacts, including avoidance of complicity and remediation where necessary.

ISO 26000’s strength lies in its strategic orientation, which supports organizational governance, culture, and decision-making systems consistent with HRDD principles.

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4. EU Corporate Sustainability Due Diligence Directive (CSDDD)

4.1 Overview and Scope

The Corporate Sustainability Due Diligence Directive (CSDDD, Directive 2024/1760) is an EU law that entered into force in July 2024 and will be transposed into national laws by July 2026, with phased compliance deadlines from 2027 through 2029. It legally mandates HRDD for large companies operating in or into the EU and extending to their subsidiaries and value chains. The directive requires companies to identify, assess, prevent, mitigate, and bring to an end adverse human rights and environmental impacts across business relationships.

CSDDD applies to companies above specified employee and turnover thresholds, with staggered application based on size and global turnover. It also includes non-EU companies with significant economic presence in the EU.

The EU CSDDD (Corporate Sustainability Due Diligence Directive) is a landmark EU law requiring large companies to identify, prevent, and mitigate adverse human rights and environmental impacts in their operations and value chains, ensuring they are accountable for failures and must adopt climate transition plans. It applies to major EU and non-EU companies with significant EU presence, establishing mandatory due diligence processes, public supervision, and private civil liability, complementing the CSRD by focusing on action (due diligence) rather than just reporting (CSRD)

4.2 Core Due Diligence Requirements

Under CSDDD, companies must undertake HRDD consistent with international standards and methodologies such as the organisation for Economic Co-operation and Development (OECD) Due Diligence Guidance and the UNGPs, by:

1. Embedding responsible business conduct into policies and management systems
2. Identifying, assessing, and prioritising adverse impacts
3. Preventing, ceasing, or mitigating actual and potential adverse impacts
4. Verifying, monitoring, and evaluating the effectiveness of measures
5. Communicating publicly on due diligence
6. Providing remediation where impacts occur
   as specified in the directive’s legal text and corresponding EU documents.

4.3 Alignment with UNGPs

Academic and professional analyses note that CSDDD’s HRDD requirements broadly align with the UNGPs, particularly around risk prioritisation based on severity and likelihood and the framework of involvement (cause, contribute, directly linked) for assigning responsibility. This alignment supports coherent integration between voluntary standards and binding regulatory duties.

4.4 CSDDD and Labour Rights Standards

Labor rights are explicitly emphasised under CSDDD through references to ILO conventions and core labor principles as part of adverse impacts companies must consider, reinforcing the connection between international labor standards and legally mandated HRDD.

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5. Corporate Sustainability Reporting Directive (CSRD) and Reporting Obligations

CSRD complements CSDDD by requiring large companies to disclose sustainability-related information, including human rights due diligence processes, performance, and outcomes, in accordance with European Sustainability Reporting Standards (ESRS). This regulatory regime serves as the disclosure layer of due diligence obligations, making HRDD processes transparent to investors, stakeholders, and affected communities.

While CSRD focuses on reporting, CSDDD mandates action and accountability — together they constitute a regulatory ecosystem that integrates HRDD throughout corporate governance and public communication channels.

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6. Comparative Analysis: Voluntary Standards and Mandatory Due Diligence Law

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7. Discussion: Integrating Standards with EU Law

7.1 Convergence and Synergies

There is a clear convergence between voluntary HRDD logic articulated in the UNGPs and the legal duties under CSDDD/CSRD, particularly regarding risk-based due diligence, transparency, corrective measures, and stakeholder engagement. Integrating voluntary standards into compliance strategies can support companies in meeting regulatory obligations while maintaining ethical robustness.

7.2 Challenges and Gaps

Despite alignment, challenges remain:

• Divergent focus areas: Voluntary standards vary in scope (labor vs broad human rights vs environmental concerns).
• Operational differences: Audit-centric methodologies may not fully capture deeper, context-specific impacts required under HRDD.
• Regulatory evolution: Ongoing adjustments to EU legislation (e.g., threshold changes and scope negotiations) introduce uncertainty for compliance planning.

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8. Conclusion

Human rights due diligence has become a central organizing principle for responsible business conduct, transcending voluntary compliance mechanisms and entering mandatory regulatory terrain under EU law. The UNGPs provide the ethical foundation, while standards like SA8000, amfori BSCI, SMETA, and ISO 26000 offer operational methods that can enhance due diligence practice. The CSDDD and CSRD embed HRDD into legal obligations for large corporations, creating a multi-layered landscape where voluntary standards support regulatory compliance and strengthen human rights outcomes.

Future research should investigate the real-world effectiveness of integrated HRDD systems across sectors and geographies, especially in lower supply-chain tiers where adverse impacts remain most prevalent.

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References (Academic & Policy Sources)

• Corporate Sustainability Due Diligence Directive (EU) 2024/1760. 
• European Commission – Corporate sustainability due diligence overview. 
• CSDDD core obligations summary and phased compliance. 
• CSDDD alignment with UNGPs. 
• EU directives due diligence steps referencing OECD methodology. 
• ILO conventions in CSDDD labour standards context. 

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