Heat stress and social dialogue in Spain

Abstract

The study examines the role of collective bargaining in protecting workers from heat stress in Spain, a country that is particularly vulnerable to rising temperatures. Through an analysis of 596 collective sectoral bargaining agreements (CBAs) registered between 2020 and 2025, 14 heat action plans (HAPs), and 13 interviews with key actors, the integration of preventive measures into labor regulations is evaluated. Only 51 CBAs (8.6%) include preventive clauses that go beyond clothing measures and only 8 (1.3%) contained an adequate set of norms to address it in a more or less comprehensive manner. Company heat action plans, although more detailed and flexible, are highly heterogeneous and have limited coverage. Recent regulatory reforms in 2023 (RD-Law 4/2023) and 2024 (RD-Law 8/2024) require heat-specific measures and protocols for adverse weather events respectively, opening a window for strengthening prevention through sectoral and company agreements in the form of CBAs and HAPs. It is concluded that, despite some advanced examples, protection remains insufficient and uneven. The combination of a more precise legal framework, proactive collective bargaining and workers’ participation regarding heat stress prevention is essential to avoid the exacerbation of health inequalities in an increasingly warmer climate, especially in sectors and companies with weak union presence.

Introduction

Estimates of heat-related deaths in the coming decades vary greatly between countries, with Mediterranean countries being the most affected within Europe^{1, 2)}. Spain faces a bunch of climate change threats, like forest fires, the spread of infectious diseases, and more extreme weather events, including heatwaves and episodes of heavy rain that result in flash floods, such as the one known as the cut-off low that took place in November 2024, where up to 228 people died. Regarding extremely high temperatures, the inland and southern regions of Spain are the most prone to experiencing them. However, its effect on people’s health doesn’t only depend on absolute air temperature but also in air humidity, air speed, the acclimatization of the exposed ones, the availability of socioeconomic resources to protect against heat, among others. Heatwaves are becoming more frequent, more intense and longer lasting. As a result, a study estimated the number of heat-related deaths during the summer of 2022 in Europe at 61,672 (CI 95%=37,643–86,807), of which 11,324 (CI 95%=7,908–14,880) correspond to Spain²⁾.

National statistics on occupational safety health (OSH) and heat

Regarding working population, the percentage of workers exposed to high temperatures in Spain is 36%, compared to 23% of the EU-28 countries average³⁾. A recent survey showed similar findings, plus a low coverage of protective measures for manual workers⁴⁾. Moreover, in recent years, several cases of fatal heat strokes at work made it to the national news: two workers in the street cleaning services of the Madrid and Barcelona municipalities died from heat stress in the summers of 2022 and 2025 respectively^{5, 6)}, a worker of the company Construcciones Maygar S.L. died while pothole repairing a road during a summer heat wave in Seville province⁷⁾ and so on. Likewise, year after year, situations of extreme severity are repeated, such as that of the settlements of strawberry workers in Huelva living next to the same farms where they work in extremely precarious conditions, often informally, enduring extreme temperatures, risk of fire, and with limited access to drinking water⁸⁾. Far from constituting isolated facts, these examples are indicative of a more widespread general trend: the well-established relationship between rising temperatures and increase in occupational accidents that has been documented both internationally⁹⁾ and nationally for Spain^10,11,12).

Health effects of heat

The effect of heat is not limited to occupational accidents. Heat also causes and aggravates cardiovascular, respiratory, renal pathologies, premature births and lower birth weight^13,14,15,16). It also causes acute systemic pictures associated with an altered thermoregulation process such as fever, chills, nausea, dizziness, confusion, fainting with loss of consciousness, and heat stroke. It can cause alterations in the central nervous system, rhabdomyolysis and disseminated intravascular coagulation. Emerging evidence also suggest an association with certain types of cancer¹⁷⁾. Likewise, excessive heat compromises the reflexes and reaction capacity of workers as well as the correct functioning of installations and machines, increasing the risk of occupational accidents such as falls, being run over, entrapment, etc¹⁸⁾. Furthermore, vulnerability to high temperatures is not uniform across the population, with certain groups of workers being particularly exposed. These include informal, precarious, or low-paid workers, newly arrived migrants, and individuals with pre-existing health conditions, to name a few. Importantly, these categories are not mutually exclusive, and multiple risk factors may overlap within the same individuals. Thus, if no measures are proactively taken to address this issue, climate change will further exacerbate existing health inequalities among different groups of workers¹⁹⁾.

Aim of the paper

The ADAPTHEAT project set out to answer the question of what role collective negotiation plays in heat protection in the workplace in five European Union countries: three in southern Europe (Greece, Italy and Spain), plus the Netherlands and Hungary²⁰⁾. This particular article pictures how the Spanish social dialogue dealt with heat stress. The paper begins with a reference to the Spanish legal framework, followed by the analysis of heat stress clauses in collective bargaining agreements (CBAs) and in heat action plans (HAPs). The CBAs and the HAPs, have consequences for occupational health and safety, and they are both a result of negotiations between the employers and the employees at different levels. These two expressions of the mentioned dialogue will be examined and critically assessed in the “results” and “discussion” sections, along with identifying their relationship and limitations. For the sake of expository clarity, we maintain the same thematic order in both sections. Prior to all that, in the following section, we give the methodological keys of the analysis carried out.

Subject and Methods

To answer the question posed in the previous paragraph, first, an exhaustive analysis was made of the current legal framework dedicated to regulating heat as an occupational health and safety problem in Spain.

Secondly, to analyze the role played by collective bargaining in heat and OSH, we have relied on the examination of collective bargaining agreements (Table 1). Within the Spanish system of collective bargaining, collective agreements must be registered with the competent labor authority, the Ministry of Labor and Social Economy. This authority is responsible for ensuring that agreements are made publicly accessible through the REGCON online platform²¹⁾. The CBAs analyzed were drawn from this REGCON database. A dual criterion was applied in the selection process:

Table 1. Relation of the collective agreements analyzed.

Analyzed (or not) collective sectoral bargaining agreement (CBA)	Nbr. of CBA
CBA that have been analyzed	596 CBA
CBA that were not found (nor analysed)	65 CBA
TOTAL of CBA within the proposed scope	661 CBA

• The chronological criterion, meaning that collective agreements registered and published between 1 January 2020 and 1 January 2025 have been examined. This timeframe enables us to assess whether the most recently negotiated agreements by social partners take into account the risks that heat stress poses to workers’ health and safety.

• The territorial criterion—that is, the geographical scope to which the agreement applies. In selecting agreements for analysis, preference has been given to those with a broader territorial application. Agreements at provincial, regional (autonomous community), and national levels have been considered. The underlying reason for this is the waterfall effect of higher-level collective agreements on those at lower levels, meaning that lower-tier agreements—for instance, company-level agreements, which have not been included in this analysis—must comply with the provisions of higher-tier agreements, such as sectoral regional or national collective agreements²²⁾.

This approach also ensures that the number of workers covered by the agreements analyzed is significantly higher, but still unknown. Next, a series of keywords (in Spanish) addressing the risks associated with heat stress were defined and subsequently searched for within each document: Temperature, Heat, Summer (and their translations in Basque, Catalan and Galician), Heat Stress, Climate (and its variations), and “Meteo-”.

Third, a content analysis of various heat action plans (HAP) approved in several Spanish companies was carried out. In the absence of a better strategy, the selection of the heat action plans analyzed in this report was made on the basis of “word of mouth” among CCOO union advisors and occupational health delegates in the companies. In total, 14 action plans were collected in the period June to December 2023 and two more in June 2025. Subsequently, their content was analyzed on the basis of exhaustiveness and quality criteria previously agreed with the ADAPTHEAT working team and expert advisors composed of eight members from five European countries from universities, trade union organizations and national occupational health institutes (see complete list with quality criteria in Supplementary Table 1).

In addition, 13 semi-structured interviews were conducted with 12 key informants from different industries and territories in Spain. All the interviews were individuals, two were conducted face-to-face and the rest using telematic means. Supplementary Table 2 shows the anonymized list of the profiles of the informants interviewed. All interviewees were duly informed of their rights as participants according to the data protection law and signed a document giving their informed consent to participate in the study. All interviews were transcribed and a content analysis of the interviews was subsequently performed.

In sum, the desk research phase made it possible to identify and analyze the main means against heat: legislation, collective bargaining agreements and heat action plans. The interviews allowed to deepen the results achieved in recent years in relation to heat stress prevention, to identify barriers and facilitators, and to draw the limits of these three instruments by pointing out the improvements to be made.

Results

This section presents the main results of the analysis. The presentation is organized according to a criterion of increasing specificity, i.e. going from the most general to the most specific aspects: legislation, collective agreements and heat action plans.

OSH and heat legislation

In Spain, the General Law on Social Security determines what is considered to be an accident at work, excluding from this definition events caused by force majeure beyond the control of the employer and completely unpredictable. It unequivocally states that “in no case shall insolation, lightning and other analogous phenomena of nature be considered force majeure outside the work”²³⁾.

The Law 31/1995 on Occupational Risk Prevention²⁴⁾, which formally transposed the 1989 European Framework Directive on occupational safety and health, lays the foundations of preventive activity in Spain. According to this law, the employer is ultimately responsible for the occupational health of the workers in the workplace. This role is a consequence of his/her power to organize and direct the work activity, and therefore to create and determine the conditions of exposure to risk. However, specific regulations on heat are developed in other laws. Thus, Annex III.2 of Royal Decree Law 486/1997 on Workplaces establishes that “the environmental conditions of workplaces must not constitute a source of discomfort or annoyance for workers. To this end, extreme temperatures and humidity, sudden changes in temperature, unpleasant air currents, unpleasant odors, excessive radiation and, in particular, solar radiation through windows, lights or glazed partitions must be avoided”²⁵⁾.

The same RD 486/1997 (Annex III.3) incorporates temperature limit values for indoor workplaces, although the application of these regulations remains a challenge. Specifically, it establishes that the temperature of premises where sedentary work is carried out, typical of offices or similar, will be between 17 and 27°C (62 and 80°F). The temperature of premises where light work is carried out shall be between 14 and 25°C (57 and 77°F). The relative humidity shall be between 30 and 70 percent, except in rooms where there are risks due to static electricity, where the lower limit shall be 50 percent. Workers shall not be frequently or continuously exposed to air currents whose velocity exceeds 0.25 m/sec when working in conditions of no heat stress, 0.5 m/sec when performing sedentary work in conditions of heat stress, and 0.75 m/sec when performing active work in conditions of heat stress. These limits do not apply to air currents used expressly to mitigate heat stress, nor to conditioned air currents, for which the limit will be 0.25 m/sec in the case of sedentary work and 0.35 m/sec in other cases.

Recently, the regulation on outdoors’ occupational heat in Spain was updated with the approval of RD 4/2023²⁶⁾, which eliminates the exceptions for certain occupations and opens the door to the application of exceptional protection measures, including the adaptation of working hours, in situations of high temperature alert. RD 4/2023 establishes that when work is carried out outdoors and in those that cannot be enclosed, adequate measures must be taken for the protection of workers against any risk related to adverse meteorological phenomena, including extreme temperatures. These measures shall be derived from the occupational risk assessment, which shall take into consideration, in addition to the aforementioned phenomena, the characteristics of the task to be performed and the personal characteristics or known physical state of the worker. The measures will include the prohibition to carry out certain tasks during the hours of the day when adverse meteorological phenomena occur, in those cases in which the due protection of the worker cannot be guaranteed in any other way. Finally, in the event of severe weather warnings (orange or red level) issued by the State Weather Agency or the corresponding regional body, it will be mandatory to adjust working conditions, including the reduction or modification of the working day.

The new regulation also cites Article 23 on limitation of risk exposure times included in RD 1561/1995, of September 21, on special working days²⁷⁾. This article specifies that the measures related to the limitation or reduction of exposure times to environmental risks will be limited to the jobs, places or sections in which the risk is concrete and for the time in which the cause that motivates it subsists, without any reduction in the salary of the workers affected by this measure. Thus, the reduction of time and therefore of the activity due to adverse weather conditions cannot entail salary costs for the worker.

Recently, the socio-ecological disaster related to the cut-off low in the Valencian Community and Castilla-La Mancha, has led to the approval of a new law RD 8/2024 on extreme meteorological phenomena²⁸⁾ that seeks to guarantee the safety of workers against adverse weather risks during their working day and when traveling to and from their workplace. This regulation makes mandatory the existence of action protocols against adverse weather phenomena, including heat waves. To this end, it introduces the following amendment to the Workers’ Statute, the basic labor law in Spain, to introduce the following obligation: “Likewise, through collective bargaining, action protocols will be negotiated that include risk prevention measures specifically referring to action against catastrophes and other adverse meteorological phenomena”²⁸⁾. It also introduces a paid leave of up to four days for adverse meteorological phenomena and reinforces the employer’s obligation to inform workers “of the action measures foreseen in the event of the activation of alerts due to catastrophes and other adverse meteorological phenomena” (Article 85.1 ET)^{28, 29)}.

Collective agreements

Collective bargaining in Spain is mainly expressed through collective bargaining agreements (CBAs), which are of particular interest given that their content may address all aspects of working conditions (Art. 85 ET)^†29). In this sense, heat stress at work constitutes a working condition that can be regulated within their scope. These agreements may take various forms, including statutory and non-statutory agreements, framework agreements, or specific accords on particular matters. Collective agreements vary in their scope of application, ranging from national, regional (autonomous communities), and provincial sectoral agreements to company-level agreements. In this section, we focus on sectoral agreements covering at least the provincial level or higher, as this extends their applicability to a broader group of workers.

In this study a total of 661 CBAs were identified in a first search, of which access was successfully obtained for 596. The remaining 65 agreements could not be accessed due to incorrect links in the database, and no results were found upon consultation of the corresponding official bulletins (Table 1).

As pictured in Table 2, a total of 414 agreements (approximately 69%) make no reference whatsoever to heat stress, underscoring the marginal status of this growing hazard within collective bargaining agendas. Conversely, 182 agreements (31%) include some form of reference to heat-related risks. However, the depth and quality of these references vary considerably. The majority of these CBAs (131) rely heavily on clothing as the primary or sole preventive measure.

Table 2. Classification of collective sectoral bargaining agreements (CBAs) according to heat stress clauses inclusion.

Type of clauses regarding heat stress-related risks	Nbr. of CBA
CBA with no reference to heat stress at all	414 CBA
CBA that, somehow, referred to heat stress	182 CBA
Only refer to clothing	131 CBA
Clauses different than clothing	51 CBA
Reference to heat stress	14 CBA
CBAs that include an adequate set of heat stress management norms	8 CBA
Reference to Wet Bulb Globe Temperature (WBGT)	0 CBA

A closer examination reveals further limitations in the way heat stress is conceptualized and addressed. Only 51 CBAs (8.6%) include preventive clauses that go beyond clothing measures, such as organizational or technical ones. Even more concerning, a mere 14 agreements explicitly refer to the concept of “heat stress”, and only 8 (1.3%) contained an adequate set of norms to address it in a more or less comprehensive manner. These CBAs are deployed in the following sectors: construction (5), metal (2) and agriculture (1). No agreement refers to objective scientific indicators, such as the Wet Bulb Globe Temperature (WBGT), which are critical for accurately assessing heat stress³⁰⁾.

Regarding the concrete clauses that address heat stress in collective agreements, these can be grouped into eight distinct categories. Although their scope is limited, they introduce useful and diverse measures that can serve as a foundation for improving protection against heat in the workplace.

1. Adjustment of working hours and work organization in response to heat. This group includes clauses that provide for changes in working hours or shifts as a response to high temperatures, aiming to reduce workers’ exposure to heat. e.g. “On days when extreme heat is anticipated, a compressed work schedule shall be implemented, while respecting the working time established for a normal day”.

2. Risk assessment, environmental monitoring and preventive planning. This group brings together clauses focused on the identification and control of heat stress through risk assessments, environmental measurements, and preventive planning. e.g. “Every workstation with potential exposure to physical agents such as heat shall be evaluated, with prior notification given to the health and safety representatives”.

3. Work suspension and compensation due to adverse weather conditions. These clauses regulate the suspension of work due to extreme weather and set out the terms for compensation or recovery of lost hours. e.g. “If the worker presents themselves at the workplace and the work must be suspended before commencing, 50% of the wage shall be paid”.

4. Training, information and awareness-raising on heat stress. This group encompasses provisions promoting the training of workers and their representatives on heat risks and protective measures. e.g. “Preventive training shall include specific content on exposure to extreme temperatures and heat stroke”.

5. Equipment, infrastructure and heat comfort measures. These clauses ensure adequate material conditions such as access to drinking water, shaded areas, work clothing, climate control systems, and other facilities to mitigate heat exposure. e.g. “A shaded area with drinking water shall be provided for hydration, along with rest areas protected from the sun”.

6. Trade union participation, joint committees and climate-related bargaining. This group comprises clauses that reinforce the role of worker representation bodies in addressing heat stress, including the establishment of specific committees or negotiated protocols. e.g. “The signatory parties to the agreement shall adopt a protocol serving as a practical guide to mitigate the harmful effects of heat waves”.

7. Specific measures for vulnerable groups or physically demanding tasks. These clauses address the need for particular protections for pregnant or breastfeeding workers, or for those engaged in tasks under especially harsh conditions. e.g. “All companies must carry out specific risk assessments for situations of pregnancy and breastfeeding, taking into account temperature and other physical agents”.

8. Legal references and general provisions without specific measures. This group consists of clauses that refer to legislation or regulatory standards on extreme temperatures without incorporating any concrete measures in the agreement itself such us sending to the content in force under the RD 4/2023²⁶⁾.

Heat action plans

The need to manage heat at work emerged decades ago, hence the clauses on compressed work schedule in collective agreements such as those of the construction sector in some provinces of the south of the country. However, this is not the only negotiated instrument at disposal to manage heat at work. The so-called heat action plans (also known as heat protocols) have also been tested in recent years as instruments for the prevention of heat stress at work^{19, 31)}. HAPs usually take the form of a protocol for action within a company or a workplace, although they can sometimes be generalized to an entire sector. They activate when a certain level of heat is reached. A HAP establishes a set of procedures for each warning level. They are negotiated and eventually agreed between the company and the workers, to determine, at any given time, whether the environmental conditions increase exposure to heat stress, creating a level of risk that makes it necessary to adopt additional measures to the usual ones, in order to protect the health and safety of workers. These agreements, when signed, and unless otherwise expressed, are binding, but unlike CBAs, they don’t need to be published in any official gazette (Table 3).

Table 3. Steps to complete a heat action plan^{19, 31)}.

1	Formation of a working group with the participation of company and worker representatives.
2	Choice of the evaluation and monitoring method with attention to varying risk levels.
3	Climate risk communication system.
4	Selection of preventive measures for each hazard scenario (risk level) taking into account the characteristics of each job.
5	Determination by the company of the persons responsible in each workplace for checking compliance with the plan, the level of risk and communicating the measures to be adopted at the beginning of each shift or day.
6	Planning the response to emergencies related to heat-related diseases.
7	Training and information so that the workforce is aware of the action plan and is able to identify early symptoms of heat stress-related illnesses.
8	Periodic evaluation of the effectiveness of the plan and planning for improvements.

The 14 heat stress action plans analyzed in this work are listed in Supplementary Table 1. The first column of the table includes all the quality indicators chosen jointly by a group of expert members of the ADAPTHEAT project²⁰⁾ in the early stages of the project, as explained in the methods section. They can be divided in four subgroups: definition of occupational heat stress, heat stress monitoring and evaluation, negative impacts to be avoided, actions to be taken. The columns to the left are the heat action analyzed. They belong to companies from sectors such as: agriculture, construction, water management, public sanitation and street cleaning, urban gardening, textile industry, hospitality industry, retail, airport ground staff, and regional public administration employees, as indicated in the first row.

Three quarters of the plans were co-determined with the workers, while the rest were drawn up by an independent prevention service hired by the company. Compliance with the plan is binding on the employer in about half of the cases. Approximately half of the plans are implemented during the summer months and half throughout the year. Less than one third of the plans include a technically validated methodology for heat stress risk assessment and only one in three plans explicitly provide for its update. Real-time monitoring of on-site thermohygrometric conditions is virtually non-existent, which contravenes technical recommendations. Instead, the majority of plans rely on state or regional weather agency heat warning systems that only take temperature into account. The limit values are set based on meteorological, not health, criteria and also do not take into account the metabolic rate associated with the workload or the clothing. There are five plans that do establish a limit value based on the combination of humidity and temperature provided by the heat index, although it is not clearly stated how this measurement will be carried out. Most plans establish specific preventive measures for each of the alert levels. Among the specific measures or actions in each plan, the most common are hydration and organizational measures (adaptation of schedules, breaks, etc.), since they appear in all the examples analyzed. The thermal and breathability properties of clothing are also very frequent, followed by the recognition of symptoms and the establishment of emergency measures. Only one of the plans analyzed measures heat strain in real time using wristbands^‡. Coexistence with other hazards (e.g. chemical, biologic, etc.) and how to manage their combined exposure are not usually taken into account. Health surveillance and medical check-ups are only included in six of the 14 analyzed plans. Less than half of the plans include training. In contrast, it is relatively common for plans to include prevention of adverse health effects beyond heat stress, including prevention of solar ultraviolet radiation. Thermal comfort, on the other hand, is hardly considered. Nor are chronic diseases related to heat exposure. Most of them distinguish between activities and jobs, which is essential to ensure the effectiveness of the implemented measures. In four of the plans analyzed, emergency actions are excluded from the plan’s measures. The majority of the plans also take into account, albeit nominally, the special needs of certain groups of workers: pregnant women, new recruits, workers returning to their jobs, people with health problems, etc. For more details, see Supplementary Table 1.

Discussion

Legislation

After more than 26 yr without updating the regulations—coinciding with what has been the hottest period since records began³²⁾—legal progress on heat and OSH finally resumed in 2023. Detailing concrete heat prevention measures such as the adaptation of schedules as in RD 4/2023 may contribute to a greater sensitivity to this risk factor, which otherwise tends to be considered inevitable or “natural” and given by default. In addition, RD 4/2023 stresses the obligation, already established in prior OSH norms stemming from the transposition of the European Framework Directive³³⁾, to take into account the characteristics of the task and the personal characteristics or known biological state of the worker when carrying out the heat stress risk assessment. The amendment also extends protection to environments that were previously excluded from the previous legislation, such as fishing boats, temporary or mobile construction sites, crop fields and means of transport used outside the workplace, all of which are contexts with critical exposure to heat. Finally, it eliminates Point 5 of Annex III of RD 486/1997, which did not sufficiently protect from heat to outdoor workers^††. However, ambiguity is still existent as Point 4 of the same regulation is not clear enough when establishing limitations. Concretely, it states that “For the purposes of applying the provisions of the previous paragraph, account must be taken of the limitations or conditioning factors that may be imposed, in each case, by the particular characteristics of the workplace itself, the processes or operations carried out in it and the climate of the area in which it is located”²⁶⁾.

This RD 4/2023 is by no means an ex nihilo creation, but has clear precedents in sectoral regulations and in collective bargaining. Thus, RD 4/2023 was preceded by a set of sectoral regulations that offer guidelines that are now reflected in this general rule: Article 24 of RD 1561/1995 on work in the field²⁷⁾, the Article 166 of the VI General CBA of the Construction Sector in the construction sector³⁴⁾, and RD 1216/1997 in the fishing sector³⁵⁾. This can be described as a “virtuous” feedback between collective bargaining and legislation³⁶⁾.

However, these regulations still have some important limitations. For example, it still does not legally establish a specific scientifically validated heat stress assessment system. While it is true that the official guidelines and technical notes from the Spanish National Institute for Occupational Safety and Health include methods scientifically and technically backed^37,38,39,40), in practice, the choice of method remains in the hands of the protective and preventive services. Finally, it should be noted that the provided heat alerts are indicative but insufficient to support comprehensive preventive activity against heat stress, since they are designed to warn the general population and do not include key occupational aspects such as the intensity of physical activity, clothing and environmental parameters other than temperature. In short, RDL 4/2023 is a step forward by eliminating the arbitrary exclusions of the previous regulation and incorporating outdoor work, but further progress must be made in the legal field.

Collective agreements

The analysis of collective agreements reveals a significant gap in the regulation of occupational risks related to heat stress. The majority of agreements reviewed lack any specific clauses addressing the prevention of such risks. Although collective bargaining mechanisms hold the potential to address climate-induced occupational hazards, this potential remains largely unrealized. The findings underscore the urgent need for collective bargaining to assume a more proactive and comprehensive role in regulating heat-related risks. This could be addressed through different legal tools such as obligatory action plans including a more comprehensive protection against heat stress at work.

Where references to heat stress are present, the predominant focus lies on the provision of clothes adapted to the summer time. However, this reliance on clothing as the primary preventive measure is inconsistent with established occupational health and safety frameworks, particularly a hierarchy of controls, which prioritizes elimination, substitution, technical, and organizational measures before resorting to personal protection⁴¹⁾. This misalignment suggests a limited understanding of prevention principles and highlights the need for improved integration of occupational health standards into collective agreements.

Conversely, certain agreements include clauses that may inadvertently exacerbate heat-related risks. A notable example is the inclusion of financial incentives, such as hazard pay, for work conducted under extreme temperatures or working overtime to prevent the harvest from being lost due to high temperatures (getting an extra pay on exchange). They do so without introducing any preventive or mitigating measures. As a result, they risk normalizing exposure to hazardous hot environments rather than reducing or eliminating the underlying risk. A total of 21 CBAs contained clauses such as these in the sample analyzed.

The analysis also reveals important terminological and technical shortcomings. Explicit references to “heat stress” are rare, and none of the agreements examined make use of objective assessment tools such as the WBGT index or similar indicators that are more scientifically accepted. This lack of technical language and scientific standards reflects a broader disconnect between collective bargaining instruments and contemporary occupational health knowledge. Bridging this gap is essential to ensure that collective agreements respond adequately to the evolving climate context and uphold the right to safe and healthy working conditions.

Finally, a small subset of CBAs showed promising practices. These texts adopt more integrated and multi-layered approaches to heat stress, encompassing a combination of organizational, technical, and protective strategies. Such agreements illustrate the potential capacity of collective bargaining to generate innovative and effective solutions, and they merit recognition as examples of good practice that could inform future negotiations. A key feature shared by most of them is the automatic activation of protective measures upon the issuance of official meteorological alerts, specifically orange or red warnings from the national weather agency (AEMET as per its Spanish acronym).

Another distinguishing element is the incorporation of concrete and dynamic measures and strategies. These include, for instance, the prioritization of alternative tasks that do not involve exposure to high temperatures, as well as a detailed catalogue of permissible adjustments to working time—such as advancing, delaying, interrupting, or fragmenting the workday. This provides clear operational guidance to employers and workers alike. Several clauses specify that such adjustments must be agreed upon with worker representatives, and they include guarantees that no disciplinary action shall be taken against employees unable to adapt to new schedules for justified reasons such as care responsibilities.

Some agreements also go beyond emergency adaptation and include measures for medium- and long-term prevention, such as regular maintenance and inspection of climate control systems, training on early signs and symptoms of heat-related illness, and the provision of shaded or air-conditioned rest areas. A particularly noteworthy aspect is the explicit recognition of individual vulnerability, requiring that risk assessments consider personal or physical characteristics of workers (e.g. pregnant women), including pre-existing health conditions or disabilities.

Overall, these clauses mark a substantial improvement over the more fragmented and limited provisions previously examined. They combine anticipatory planning, technical precision, participatory governance, and legal safeguards in ways that reflect a more systemic understanding of heat stress as an occupational risk. As such, they may serve as reference models for sectoral or company-level agreements aiming to better protect workers in the context of rising temperatures and increasing frequency of extreme weather events.

The vast majority of the collective bargaining agreements analyzed have considerable room for improvement in terms of protecting workers against the risks of high temperatures. It is reasonable to think that the agreements are too broad to correctly reflect the prevention needs of individual companies. However, it is advisable that they incorporate more and better preventive measures, protection, information, etc. against heat in their final wording. First, because fulfilling the legal obligation is reported to be the main reason to manage OSH by 87% of establishments in the EU-27⁴²⁾. Second, because due to the characteristics of the Spanish productive fabric, with a high proportion of small companies without union representation, negotiation of action plans against heat is challenging.

Heat action plans

HAPs are more comprehensive than CBAs in terms of the number and variety of heat prevention dimensions that they cover. They are also more flexible than a CBA when it comes to negotiating and modifying them. However, so far they are an uncommon solution since they were not mandatory and they were usually the fruit of the pressure exerted by workers representatives in the health and safety committees. Therefore, nowadays HPAs do not cover the vast majority of the working people. This situation might change with the introduction of adverse weather events as a mandatory subject of collective bargaining as a result of the recent approval of RD 8/2024²⁸⁾. It will depend on how this regulation is specified, on the deadlines for implementation (which are not specified in the new law), and on the willingness of the institutions in charge of ensuring compliance with the law. Having a clear HAP can make the difference in a heat emergency situation, as it reduces improvisation and inefficiencies in critical moments.

Most heat action plans involve participation from workers’ representatives and are binding, but not always. The number of HAPs has increased significantly following the approval of RD 4/2023, which shows that delegates do not act in a vacuum, but that legislation is key to producing tangible and concrete results in collective bargaining, as well as conditioning the form these results take. In their favor is the fact that they make it possible to translate the principles of prevention into the concrete reality of the company (or sector). However, there is a high degree of heterogeneity in the quality and degree of completeness of the examined plans. They vary greatly from one to another, influencing the scope and effectiveness of the resulting preventive action. Some plans have significant ambiguities in the definition of key concepts such as heat stress. Most plans base their risk levels on an indicative public warning system intended for the general population rather than the working population. The optimum to establish on-site measurement systems for temperature and humidity and control them every hour. On the positive side, this mechanism shifts the response from a discretionary to one that is rule-based and predictable, enhancing legal certainty and enforceability. Except in two cases (agriculture and construction sectors), the plans analyzed are company or work center plans. This allows them to be specific and adapted to particular jobs, but limits their coverage. The majority of the working population does not have a heat action plan⁴⁾. Moreover, the action plan for the construction industry was subsequently included in the collective bargaining agreement³⁴⁾. In this case, the action plan was a preliminary step to the development of a more complete and substantive collective bargaining agreement on this issue. We do not have sufficient evidence to make a generalization in this respect with respect to the rest of the plans. It is important to note, however, that the best results and the most ambitious plans are observed in those companies where the dialogue on health and safety issues between representatives of the company and the workers is fluid and sustained over time. Thus trust and willingness to cooperate of the two parties is key to achieving an optimal result in this regard.

The limitations of the study regarding HAPs, have mainly to do with a selection bias in the selection of the plans analyzed. There is no database that systematically records the protocols signed internally between unions and companies in this area. The documents analyzed are not a representative sample of the heat action plans currently in place in Spain, but only of those to which we have had access so far. Unlike what happens with collective bargaining agreements, there is neither a legal register nor a repository on preventive action against heat in companies. However, we are not aware of the existence of other lists including a higher number of examples and we believe that it constitutes a useful starting point to begin to evaluate its strengths and weaknesses. In terms of the strength of this analysis, it is worth highlighting the completeness of the criteria for evaluating the plans, which was created by a panel of international experts in the field taking part in the ADAPTHEAT project.

Concluding remarks

The foreseeable magnitude of climate change’s impact on the health of the working population, together with the virtuous feedback dynamics between OSH and heat-stress regulations, collective bargaining, and workers’ participation in preventive matters, compels us to take action simultaneously on all the fronts analyzed. The progress achieved in recent years through social dialogue in the three domains examined in this article—legislation, collective bargaining agreements, and heat action plans—must continue to deepen. Occupational safety and health legislation on heat-related stress must eliminate the ambiguities it still carries; collective bargaining must be systematically strengthened in the field of occupational and environmental health and safety; and heat action plans must be expanded and improved in both technical quality and comprehensiveness. Nonetheless, to ensure that these measures have the intended effects, it will be essential to accompany them with strict compliance by employers. Public regulations and binding agreements in the sectoral and company levels (in the form of CBAs and HAPs), must be effectively monitored by the competent public authorities, as well as by workers’ legal representatives and trade unions.

Conflict of Interest

None.