Royal Decree 846/2026 tightens occupational exposure limits for lead and adds values for diisocyanates

Spain's Official Gazette (BOE) of 23 October publishes Royal Decree 846/2026, of 21 October, amending two core pieces of Spanish prevention law: Royal Decree 665/1997, on protecting workers from risks related to exposure to carcinogenic, mutagenic or reprotoxic agents, and Royal Decree 374/2001, on protection against chemical agents at work. The decree has been in force since 24 October, the day after publication.

It transposes Directive (EU) 2024/869 of the European Parliament and of the Council as regards limit values for lead and its inorganic compounds and for diisocyanates. For law firms advising companies with chemical risk, and for prevention services, it is immediately applicable law that should be folded into risk assessments without delay.

What changes for carcinogens and reprotoxins

The amendment of Royal Decree 665/1997 revolves around lead. The text starts from a scientifically relevant premise: it is not possible to determine a level below which exposure to lead and its inorganic compounds is safe for the offspring of workers of childbearing age. Lead is therefore classified as a non-threshold reprotoxic agent, its binding occupational exposure limit value is reduced in Annex III, and the binding biological limit value is updated in the new Annex III bis.

The decree also adds a sole transitional provision setting the biological limit value for lead and its inorganic compounds until 31 December 2028, giving companies a staggered calendar to adapt measurements and protocols. Article 8, on health surveillance, is adjusted to coordinate with Article 6 of Royal Decree 374/2001, and the first final provision is amended so that the Technical Guide of the National Institute for Occupational Safety and Health will include guidance on biological monitoring of lead-exposed staff, with special attention to women of childbearing age.

Two practical details should not be missed. First, the preventive training required by the decree, in compliance with Articles 18 and 19 of the Occupational Risk Prevention Act, must be both theoretical and practical. Second, personal hygiene time for exposed workers is capped at ten minutes before each meal, on the understanding that any food intake requires prior hygiene.

Diisocyanates enter the chemical agents rules

In Royal Decree 374/2001, the main novelty is the inclusion of diisocyanates in Annex I with their own binding occupational exposure limit value, accompanied by a transitional provision keeping specific values until 31 December 2028. At the same time, Annex II drops the limit value for lead and its derivatives, which moves into Royal Decree 665/1997 to unify its regime.

Diisocyanates are present in the manufacture and application of polyurethane foams, paints and adhesives, and their express regulation will force companies that handle them to review their risk assessments: environmental measurements, protective equipment, specific training and health surveillance will all have to be adjusted to the new values.

What to review now

For labour and prevention advisory work, the decree sets out a concrete work programme: identify positions with exposure to lead or diisocyanates, check whether current environmental measurements remain valid under the new limits, update biological monitoring protocols - especially for workforces including women of childbearing age exposed to lead - and document theoretical-practical training. The Labour Inspectorate has had an in-force text since 24 October, although the transitional regime until the end of 2028 offers room for adapting the transitional biological and environmental values.

At Agente Lex we have followed the evolution of prevention rules and their impact on business advice, from our guide on occupational risk prevention in law firms to the information duties under Royal Decree 723/2026 on information to workers. Those planning workforces and calendars for the coming year can also check the 2027 public holidays and, for the growing business, our guide on hiring your first employee, where risk prevention appears as one of the first obligations to cover.

The full official reference can be found in the text of Royal Decree 846/2026 in the BOE.