Companies handling diisocyanates and lead must update chemical exposure protocols

The Spanish Government has enacted Real Decreto 846/2026, of October 21, which modifies the existing legal framework regarding worker protection against chemical agents. This regulation, published in the BOE, specifically amends Real Decreto 665/1997 and Real Decreto 374/2001 to align national law with European Directive (UE) 2024/869. The primary objective is to refine the protection of workers against risks related to exposure to carcinogens, mutagens, reprotoxic agents, and general chemical agents during professional activities.

What changes

The new regulation introduces two fundamental shifts in the technical management of chemical risks in the workplace. First, it incorporates the environmental exposure limit for diisocyanates into Annex I of the regulatory framework. This change ensures that companies using these substances are subject to specific, measurable thresholds to prevent health damage. According to the second transitory provision of the decree, these specific environmental exposure limits for diisocyanates will be applicable until December 31, 2028.

Second, the regulation executes a significant administrative and technical transfer regarding lead and its derivatives. Previously regulated under the general chemical agents framework (Real Decreto 374/2001), lead is now integrated into the specific framework for carcinogens, mutagens, and reprotoxic agents (Real Decreto 665/1997). This transfer is not merely formal; it implies that lead must now be managed under the more stringent preventive protocols required for substances with high biological impact. Furthermore, the regulation reduces the environmental exposure limit for lead and its inorganic compounds in Annex III and updates the binding biological limit value in Annex III bis.

Finally, the regulation mandates that the Technical Guide developed by the National Institute for Safety and Health at Work (INSST) must include a list of hardwoods and specific instructions regarding the biological control of personnel exposed to lead, with a particular emphasis on protecting female workers of childbearing age.

Context

This regulation is part of a continuous effort to transpose European Union directives into Spanish law, specifically Directive (UE) 2024/869. To understand the current landscape, it is necessary to look at the previous legal structure. For years, the protection of workers was split between two main pillars: Real Decreto 665/1997, which focused on the most dangerous agents (carcinogens and mutagens), and Real Decreto 374/2001, which covered general chemical risks.

By modifying both decrees, the legislator is correcting a fragmentation in the regulation of highly hazardous substances. The move of lead from the general chemical decree to the carcinogen/reprotoxic decree reflects a scientific consensus on the severity of lead exposure. This alignment ensures that the most rigorous preventive measures—such as specific biological monitoring and stricter exposure limits—are applied consistently across all high-risk substances. The regulation also reinforces the legal certainty of the Spanish occupational health system by harmonizing national thresholds with the latest European standards.

Who is affected and how

Large companies and industrial sectors: This group faces the highest impact, particularly those in the chemical, pharmaceutical, and manufacturing sectors. Companies that utilize diisocyanates in their production processes (such as polyurethane manufacturing) must immediately reassess their technical ventilation and monitoring systems to comply with the new Annex I limits. Those handling lead must migrate their entire prevention and health surveillance protocols from the old RD 374/2001 framework to the RD 665/1997 framework.

SMEs (Small and Medium-sized Enterprises): SMEs involved in specialized manufacturing, construction, or chemical processing that employ workers exposed to hazardous substances are obligated to update their Risk Prevention Services (Servicios de Prevención). Even if the company is small, if the chemical risk is present, the legal obligation to monitor biological limits (especially for lead) is non-negotiable.

Self-employed professionals (Autónomos): Self-employed individuals who employ workers in environments where chemical agents are present—such as specialized workshops or small-scale chemical handling—must ensure that their occupational risk assessment (Evaluación de Riesgos) reflects the updated limits for diisocyanates and the new regulatory home for lead. Failure to do so could result in non-compliance with occupational health and safety standards.

What to do and when

The regulation entered into force on the day following its publication in the BOE, which corresponds to October 24, 2026 (Disposición final tercera). Because the law is already in effect, companies should not delay their adaptation. The following actions are recommended:

• Update Risk Assessments: Review all existing risk assessments involving diisocyanates to ensure they incorporate the new environmental exposure limits specified in Annex I.
• Protocol Migration: For companies managing lead, integrate all prevention, training, and health surveillance protocols into the framework of Real Decreto 665/1997.
• Biological Monitoring: Implement or update biological monitoring programs for workers exposed to lead, ensuring specific attention is paid to the requirements for female workers of childbearing age as indicated in the new provisions.
• Technical Review: Consult the updated Technical Guide from the INSST to ensure that the control of hardwoods and lead exposure meets the new legal requirements.

Given the technical complexity of these chemical limits and the legal implications of mismanaging biological monitoring, we recommend contacting the occupational health and safety area of BMC to evaluate your specific industrial processes and ensure full compliance with the updated thresholds.