Carcinogenic, mutagenic and reprotoxic agents

What are carcinogenic, mutagenic, and reprotoxic agents?

A carcinogen can cause cancer or increase its incidence; a mutagen induces heritable mutations in germ cells; a reprotoxicant produces adverse effects on sexual function and fertility or on the development of offspring. In Spanish labor law, Royal Decree 665/1997 defines these agents by reference to categories 1A and 1B of the CLP Regulation and adds certain substances, mixtures, and processes in its Annex I (for example, work involving exposure to hardwood dust, respirable crystalline silica generated in a work process, or diesel engine emissions ).

European regulations stem from Directive 2004/37/EC, amended several times to expand the list of agents with binding limit values ​​and to incorporate, through Directive (EU) 2022/431, substances toxic to reproduction. Spain has transposed it through successive amendments to Royal Decree 665/1997, the most recent being Royal Decree 612/2024, which extends its scope to reprotoxicants and distinguishes between reprotoxicants with and without thresholds for the purposes of applicable measures.

This is a stricter regime than the general one for chemical agents in Royal Decree 374/2001: substitution is not a preferred option but an obligation when technically possible, and the reduction of exposure must be brought to the lowest technically possible level, regardless of whether the limit values ​​are respected.

Obligations of Royal Decree 665/1997

• Identification and assessment (Article 3). Assess the nature, degree and duration of exposure by all routes, including dermal, with special attention to particularly sensitive workers; periodic review and in case of changes.
• Substitution (Article 4). Avoid the use of the agent by replacing it with another non-hazardous or less hazardous agent whenever technically possible; document the results of the investigation of alternatives.
• Prevention and reduction (Article 5). If substitution is not possible, produce and use the agent in a closed system; if that is also not possible, reduce exposure to the lowest technically possible level, without exceeding the limit values ​​in Annex III, by limiting quantities and exposed persons, process design, local exhaust ventilation, hygiene measures, signage, collective and individual protection, and procedures for incidents and storage.
• Hygiene and personal protection measures (Article 6). Prohibition of eating, drinking or smoking in risk areas, protective clothing, separate places for work clothes and street clothes, time for hygiene during the workday and washing and decontamination at the employer’s expense.
• Accidental and non-regular exposures (Article 7). Procedures for accidental exposures and for non-regular activities with foreseeable exposure, with restricted access and specific protection.
• Health surveillance (Article 8). Specific surveillance before exposure, at regular intervals and when alterations are detected; the individual medical record provided for in Article 8.3 must be kept, in accordance with Article 9.3, for at least forty years after the end of exposure in the case of carcinogenic or mutagenic agents and for at least five years in the case of reprotoxic agents.
• Documentation, information and training (articles 9 to 12). Updated list of exposed workers with exposures and results, kept for forty years; information to the labor authority; adequate information and training and consultation of representatives.
• Limit values ​​(Annex III). Binding limit values ​​for agents such as benzene, vinyl chloride, hardwood dust, chromium VI, respirable crystalline silica, formaldehyde, diesel engine emissions and others, consistent with the INSST occupational exposure limits document.

Frequent exposure agents and situations

• Respirable crystalline silica. Cutting, drilling, polishing and machining of stone, concrete, ceramics and quartz agglomerates.
• Asbestos. Also regulated by Royal Decree 396/2006 in work with risk of exposure.
• Hardwood dust. Carpentry, joinery and furniture making.
• Chromium VI, nickel and other metals. Chromium plating, welding of stainless steels and surface treatment.
• Benzene, formaldehyde, and classified solvents. Chemical industry, laboratories, healthcare, and materials preservation.
• Diesel engine emissions. Workshops, mining, logistics, and spaces with operating vehicles.
• Hazardous drugs. Preparation and administration of cytostatics and other drugs in healthcare settings.
• Reprotoxicants. Lead and its compounds, certain phthalates and solvents, with attention to the protection of maternity and breastfeeding.

Organizational application: how to manage exposure

1. Inventory the substances and mixtures classified as carcinogenic, mutagenic or reprotoxic of category 1A or 1B from the safety data sheets, and the procedures of Annex I present in the activity.
2. Evaluate exposure by task and route of entry, with measurements where appropriate, and compare it with binding limit values ​​and the technically lowest possible level criterion.
3. Document the investigation of alternative replacements and the technical reasons when it is not possible.
4. Implement closed systems or, failing that, localized extraction, ventilation, limitation of exposed persons and quantities, and work procedures, with individual protection as a complement.
5. Organize hygiene measures, work clothing management, and restricted access areas.
6. Establish specific health surveillance with the prevention service and maintain the list of exposed individuals and their histories for forty years.
7. Train and inform exposed persons and consult with representatives, and communicate the required information to the labor authority.

Preventive management software allows you to maintain the inventory of agents and tasks, measurements, the list of exposed individuals with their retention periods, and the traceability of health surveillance and training.

Limits and common mistakes

1. Apply the general regime for chemical agents and not the reinforced regime of Royal Decree 665/1997 when the agent is classified as carcinogenic, mutagenic or reprotoxic.
2. It is not enough to consider that respecting the limit value is sufficient; the standard requires reducing exposure to the lowest technically possible level.
3. Do not document the replacement investigation or the technical reasons for its impossibility.
4. Forget about Annex I procedures that do not depend on a purchased substance, such as stone cutting with silica generation or diesel engine emissions.
5. Retain the documentation for periods shorter than the required forty years.
6. Failure to integrate maternity and breastfeeding protection into the management of reprotoxicants.

The list of agents, limit values ​​and obligations have been modified on several occasions; the consolidated text of Royal Decree 665/1997 and the INSST annual document on occupational exposure limits should be consulted.

Regulatory framework in Spain

• Royal Decree 665/1997, of May 12. Protection of workers against risks related to exposure to carcinogenic, mutagenic or reprotoxic agents during work.
• Royal Decree 612/2024, of July 2. Amendment of Royal Decree 665/1997 to incorporate reprotoxic agents and transpose Directive (EU) 2022/431.
• Directive 2004/37/EC of the European Parliament and of the Council of 29 April 2004. Protection of workers from the risks related to exposure to carcinogens, mutagens or reprotoxic agents at work.
• Occupational exposure limits for chemical agents in Spain, INSST . Annual document with environmental and biological limit values.
• Royal Decree 374/2001, of April 6. General regime of protection against chemical agents, applicable in a complementary manner.

Regulation (EC) 1272/2008 (CLP) establishes the criteria for classifying substances and mixtures as carcinogenic, mutagenic or toxic to reproduction, and Regulation (EC) 1907/2006 ( REACH ) regulates the restrictions and authorizations of substances of very high concern.