Heat stress and social dialogue in the Netherlands: findings from the ADAPTHEAT-project

Abstract

Dutch occupational safety and health (OSH) legislation is characterized by its reliance on very general legal stipulations. The idea is that these broad, goal-oriented provisions leave room for tailor-made regulations at the company or sectoral level, leading to more effective risk management. This also goes for OSH legislation pertaining to heat at work. The general legal provisions on heat at work are to be fleshed out via social dialogue, in either collective labor agreements or ‘OSH catalogues’ at the sectoral level, or more specific arrangements at the company level. Analysis of all relevant labor agreements and ‘OSH catalogues’ reveals that these do seldom give proper guidance in managing heat at work. Most importantly, hardly any of these collective agreements contain a clear, science-based threshold for working in heat. Risk-assessment tools too are rather poor, and the proposed risk management measures in the ‘OSH catalogues’ do seldom follow the industrial hygiene strategy (prevention first, personal protection as a final resort). The Dutch approach of social dialogue at a sectoral level or company therefore is not very effective. Also, negotiating OSH standards at many different is not very efficient, and is at odds with common notions such as legal certainty, legal equality and transparency.

Introduction: Heat Stress in a Relatively Cool Country?

The Netherlands are a country with a moderate, maritime climate. For this reason, the risks of extreme heat, until recently, have attracted little attention—even if excess mortality among elderly during heat waves is a phenomenon that figures in the Dutch media every now and then. The National Institute for Public Health and the Environment (RIVM) too focuses on elderly and other vulnerable groups, such as children at primary school¹⁾. The health risks to workers, however, are much less known—apart from the risks of exposure to sun, resulting in skin cancer. Recent research indicates that some 5,000 Dutch workers annually develop skin cancer due to occupational exposure²⁾. But there is little knowledge on the health effects of exposure to heat at work, more particularly to climate induced heat (process generated heat risks in specific industries are much better known).

Still, it is clear that the Netherlands too are not immune to the effects of global warming. In fact, temperatures are rising much faster in the Netherlands than in other parts of the world. World-wide, the temperature has risen with 1°C over the last 130 yr, whereas in the Netherlands this is 1.3°C³⁾. And with rising temperatures, the attention for the risks to workers is on the rise too. The Dutch trade union Federatie Nederlandse Vakbeweging (FNV), for example, is persistently advocating attention for the issue, with increasing fervor, after a survey (n=5,500) among its members in 2021 indicated that ‘heat stress’ ranked high among the priorities of the FNV members—third after work related stress and physically demanding work. And in 2023 the Dutch Labor inspectorate (NLA) started a project on heat stress, both in response to calls from the FNV and the ADAPTHEAT-project, the results of which form the core of this paper.

The NLA project was meant to review the current labor inspectorate enforcement approach which, until recently, ranked ‘heat stress’ as ‘low priority’. And breaching the applicable legislation on heat stress is typically qualified as ‘other violation’ (meaning not a ‘serious violation’ or ‘directly fineable violation’). This implies that the labor inspectorate currently enforces the legislation in the field only if the direct effects of heat are life threatening, which is uncommon in the Netherlands. To date, the NLA has received no official notifications on this issue. Still, the outcome of the NLA-project has led to internal discussion whether or not to re-prioritize the issue⁴⁾. This is an indication that heat stress is rising on the OSH-agenda of not only the trade unions but of public authorities as well.

Still, even if there is an undisputed correlation between the number of heat days and absolute toll of heat⁵⁾, and the number of heatwaves as well as the number of heat days (defined as either ‘summer days’ (25–30°C) or ‘tropical days’ (>30°C)) in the Netherlands are clearly rising, it is hard to establish if this also leads to excess mortality among workers. This is also because, to a large extent, heat-related death often takes its tole under the guise of other diseases, such as heart attacks and kidney failure. As mentioned earlier: to our knowledge there are no known cases of acute, heat induced death at the Dutch workplace. It is also unclear to what extent excessive heat is related to DALY’s which, from a policy point of view, may be of more interest than mere mortality numbers. More specifically, there is no information on DALY’s for the working population. The RIVM are producing regular reports on work related DALY’s⁶⁾, but these do not include information on DALY’s due to heat exposure at work.

On the other hand, the number of Dutch workers that are exposed to heat at work is clearly not insignificant. As a result of the FNV survey in 2021, the issue ‘heat’ was added to the Dutch Working Conditions Survey (NEA), an annual survey among a very large sample of workers (response roughly 60,000 per survey wave). The fact that the NEA is being performed annually, makes it possible to monitor trends over time. Unfortunately, since the topic of ‘heat’ was added only in 2021, is not possible to establish whether or not there is a trend. But the findings in the 2021 NEA indicate that 4.6% of all workers are frequently exposed to heat, and 14.6% indicate that this is ‘sometimes’ the case. Five point zero percent of all workers (5.6% male, 4.4% women) indicate that they think their health is at risk due to heat, which would amount to roughly half a million workers⁷⁾. The next version of the NEA-survey addressing heat stress has been conducted in 2024. The data, however, had not been published at the time this paper was written.

To be sure, some of these workers are exposed to process-generated heat (such as ovens, furnaces or industrial machinery). But there are also some sectors where heat exposure may, for the largest part, be attributed to climatological heat—two of them being agriculture and construction. Workers in agriculture (9.5%) and construction (8.9%) are the two groups that most often report their health to be at risk due to heat.

A second question addressed in the NEA, is whether or not the respondents think that the employer should take measures to fight heat related risks, and whether or not the measures taken are considered ‘adequate’. It was found that in one third to nearly half of the working population think that the employer should indeed take measures to fight heat (clearly, this is mainly the case in sectors where heat may be a problem rather than in sectors where much of the work is being done in airconditioned offices). And in heat prone sectors, over one third of the respondents deem the measures inadequate or even indicate that these measures are missing altogether. This is an indication that not all employers do, as yet, take the issue of heat at work seriously enough—at least not in the opinion of their workers⁷⁾.

So, even if there is little knowledge in the Netherlands on the burden of disease (or even work related death) due to heat, it is highly probable that a rise in the number of heat days will also lead to more damage to workers. Moreover, given the findings of the FNV survey as well as the NEA, workers too think that heat at work is a relevant risk to be tackled.

One other indication that (climate) heat at work is a risk, is the number of complaints filed at the Dutch labor inspectorate, which very clearly correlates with the heatwaves in 2018, 2019 and 2022⁸⁾.

And even if in the Netherlands heat stress may not (yet) lead to a very serious burden of disease, it is interesting to look at the Netherlands as a case for social dialogue in this field. In general, social dialogue plays a pivotal role in Dutch occupational safety health (OSH) policy. This Dutch experience with social dialogue in OSH policy, more particularly in dealing with the risk of heat at work, may be informative for other countries as well. This was the main reason the Netherlands were included in the ADAPTHEAT-project.

Subject Matter and Methods

As part of the ADAPTHEAT-project, the Dutch research endeavored to answer—among others—the next four research questions:

- What are the main legal provisions and institutional characteristics of Dutch health and safety policy, particularly regarding heat at work?

- What are relevant examples of social dialogue pertaining to heat at work?

- To what extent do these forms of social dialogue contribute to ‘tailor made’ solutions for working in heat?

- How does the Dutch system of social dialogue rate on core principles of good regulation, such as legal certainty, legal equality, transparency, efficiency and, most importantly for experts in industrial hygiene, effectiveness?

The original research dealt with three levels of social dialogue: national (notably the Dutch Social-Economic Council), sectoral (labor agreements, ‘OSH catalogues’ and sectoral risk assessment tools), and at the company level. The present paper focuses on the intermediary, sectoral level.

Methodology

In the Netherlands, there are two forms of collective agreements in which the social partners can lay down specific provisions on health and safety at work: collective labor agreements and the quite peculiar form of ‘OSH catalogues’. Collective labor agreements first and foremost deal with labor conditions such as wages and working times, but the vast majority also contain provisions on health and safety. These labor agreements are private law agreements, struck by employers (mostly employers’ organizations) and trade unions. In case of breach of the agreements, either party can resort to the civil court in order to force the other party to comply. The Labor Inspectorate has no role to play in enforcing the stipulations in the collective labor agreements (albeit that the Ministry of Social Affairs and Employment checks if provisions in the CLA are not in breach of labor legislation pertaining to minimum wage, but this is not an OSH matter).

OSH catalogues too are agreements between the social partners (employers and trade unions), but they deal with OSH matters only. In the catalogue, sectoral social partners describe the main risks in their sector and provide preventive solutions that companies can implement to meet their legal obligations. The importance of the instrument is strengthened by the fact that, during their inspections, the Labor Inspectorate uses these agreements between the social partners as a ‘reference guide’ on what counts as ‘state of science’ in the relevant sector. The basic enforcement strategy, then, is that a company that has set up its measures according to the sectoral OSH catalogue may assume that the inspection will approve of these prevention measures. This is the reason why all catalogues must be submitted to the Labor Inspectorate for a quality test.

As part of the research, the Dutch research team analyzed nearly all 1,100 collective labor agreements and all 180 OSH catalogues. The collective labor agreements were retrieved from both a central database hosted by the Dutch Ministry of Social Affairs and Employment, as well as a database hosted by the FNV, the largest trade union federation in the Netherlands. A search was conducted using a number of likely key words, such as “heat”, “temperature”, “climate” and “unworkable weather” (which is a common issue regarding working in cold weather conditions, but in some cases also in extreme heat). This search yielded a selection of 59 sectoral labor agreements. Further analysis reduced the number of relevant agreements to 35. This means that ‘heat at work’ is a topic in only 3% of all labor agreements.

The OSH catalogues were collected in a two-step procedure. First, a bulk list was composed based on the annex to the policy rule on OSH catalogues 2019⁹⁾, supplemented by an internal file from the Dutch Labor inspectorate. The files were searched using the keywords “climate” and “Article 6.1” of the Working Conditions Decree (which addresses heat at work, see below). The search yielded 60 possibly relevant OSH catalogues (out of all 149 OSH catalogues that have been notified to the Labor inspectorate), that were then retrieved from various publicly accessible websites (with some websites having further subdivisions, especially the OSH catalogues of the sectors Building & Infrastructure and Agricultural & Greenery, as well as Rubber Industry). These websites were analyzed qualitatively, focusing on a number of specific themes that are addressed in more detail in the findings section below. A number of OSH catalogues had a strong focus on process-generated heat (e.g. industrial bakeries, rubber industry, confectionery industry). However, these were included in the analysis because lessons might be learned from these catalogues for the other sectors.

A third outcome of social dialogue between employers and trade unions are sectoral risk assessment tools, that support employers and workers in the process of risk assessment. A number of open access sectoral risk assessment tools were retrieved from the SER-hosted website rie.nl. There are dozens of these risk assessment tools, but the research focused on sectors that also had an OSH catalogue, as well as on a limited number of general purpose tools for SME’s. As not all risk assessment tools are open access, the number of cases used in the analysis was limited to 17. These were analyzed on the issue of heat at work, particularly on the question whether or not these risk assessment tools were based on a scientifically accepted methodology (WBGT, ISO 7243 and/or the NIOSH Recommended Effect Limits (REL))¹⁰⁾, and on the question whether or not these tools also point out specific risk management measures.

Next to the content analysis of labor agreements, OSH catalogues and risk assessment tools, several interviews were conducted with experts from the Netherlands Labor Authority (labor inspection), trade union representatives, and experts from branch level OSH institutions.

As part of the ADAPTHEAT project, also two in-depth case studies were conducted in two major, best practice companies. These will not, however, be dealt with in this paper.

Findings I: Background

Main legal and institutional characteristics of Dutch health and safety policy

In the Netherlands, the legal framework in occupational health and safety is intricately intertwined with the institutional and labor relations system—also known as the ‘Poldermodel’. This ‘Poldermodel’ is the name of a long-standing tradition of active and, mostly, consensual social dialogue between government, employers’ organizations and trade unions at various levels. At the national level, the two main consultative bodies are the Social-Economic Council (SER) and the Labour foundation.

The Social-Economic Council is a tripartite, independent body established in 1950 by public law¹¹⁾, consisting of representatives of employers’ associations, trade union federations and independent experts (‘Crown-appointed members’). The SER also has installed various committees, among which a committee on occupational health and safety and a committee on worker participation (co-determination). Over the years, the Council has issued numerous advices on occupational health and safety, notably on the various changes in the Working Conditions Act.

In 2009, the Minister of Social Affairs asked the SER for an advice on a 2008 report on heat stress by the Health Council of the Netherlands, but the SER has never issued such an advice. Still, in 2018 the SER started an OSH Platform, which shares information on good practices in occupational health and safety¹²⁾ and organizes meetings for networks of OSH professionals. And in 2024, the SER set up a website with information on working in (extreme) heat. Finally, the SER also hosts the website rie.nl, the aforementioned site where all sector specific risk assessment tools are gathered.

Established on 17 May 1945, the Labour foundation (Stichting van de Arbeid) is a national, bipartite consultative body organized under private law. Its members are representatives of the three largest trade union federations and the three largest employers’ associations in the Netherlands. Many of the members of the Labour foundation also participate in the Social-Economic Council. The Foundation regularly issues advice for employers and trade unions that negotiate collective bargaining agreements in industry or within individual companies. The Labour foundation also plays a major role in developing guidance in OSH matters, most importantly on how to reap the benefits of OSH catalogues¹³⁾.

The most important domain of social dialogue is at the company level—the level at which the actual OSH management is taking place. Dutch legislation bestows a strong role for workers’ representatives, most particularly works councils (in companies with over 50 employees) or staff representation bodies (in companies with 10–50 employees). One of the key elements of the Dutch Working Conditions Act (WCA) is the obligation to cooperate closely with the workers (representatives) in drafting OSH policy on the company level (Article 12 WCA). This obligation implements Article 11 of the Framework Directive 89/391/EEC. Specific legal powers for the works councils (and staff representation bodies) are laid down in the Works Councils Act (WOR, Wet op de Ondernemingsraden). This act contains provisions on various facilities for works councils, such as time off from work, a right to specific training (art. 18 WOR), the right to consult with workers (art. 17 WOR), as well as legal protection against any disadvantage because of their activities in worker participation—notably dismissal protection (article 21 WOR). Also, the Works Councils Act grants works councils a general right to information (art. 31 WOR) and, most importantly, a right of approval concerning OSH policy at the company level (art. 27 WOR). This right of approval also pertains to the obligatory risk assessment as well as specific risk management measures, e.g. to fight heat at work.

The practical experience with social dialogue at the company level is not dealt with in this paper. Still, it is important to understand this level of social dialogue, since it sets the background for the intermediary level which is the focus of this paper: the sectoral risk assessment tools, the collective labor agreements as well as the OSH catalogues.

Before turning to this level, however, it is important to briefly sketch the OSH regulatory strategy and legal framework.

Regulatory strategy: general obligations and social dialogue

The core of the current Dutch OSH legislation is geared to the system that is also at the heart of the European Framework Directive (FD). The most relevant obligations, in the light of this paper, are:

- A general duty of care put on the employer to ensure the safety and health of workers in every aspect related to the work and to draft an OSH policy at the company level (art. 3 Working Conditions Act)—hence also the health and safety of workers in situations of heat exposure;

- An obligation to assess all relevant risks (art. 5 WCA), if possible set against a threshold value (occupational exposure limit);

- An obligation to take protective measures to combat risks, preferably at source (art. 3 WCA), an approach also known as the occupational hygiene strategy (or STOP-strategy, STOP being the acronym for ‘substitution, technical and organizational measures, and personal protection equipment);

- Obligatory consultation of workers and/or their representatives both in drafting OSH policy and when taking concrete measures (art. 12 Working Conditions Act, more specific in the Works Councils Act already mentioned above);

These very general stipulations in the Working Conditions Act are detailed further in the Dutch Working Conditions Decree (WCD). This Decree contains seven chapters on various occupational risks, a.o. chapter 6 on ‘physical factors’. Article 6.1 WCD lays down a general duty of care for the employer to protect the workers against the risks of working in heat, specifying the general duty of care in article 3 WCA.

Article 6.1. Temperature

1. Taking into account the nature of the activities carried out by the workers and the physical load resulting from them, the temperature at the workplace should not cause damage to the health of the workers.

If risks may occur, the employer is expected to take protective measures. This obligation is specified in the following paragraphs in the Decree (6.1 (2) and 6.4).

Article 6.1. Temperature

2. If, because of the temperature in the workplace or by unfavorable weather conditions, damage may still be caused to the health of the employees, personal protective equipment should be made available. If the personal protective equipment made available cannot prevent damage to the health of the workers, the duration of the work activities is reduced to such an extent, or the work is alternated by a temporary stay at a location with a temperature as referred to in the first paragraph, at such a frequency that no damage is caused to the health.

Article 6.4 Protection from sunlight

Directly incident sunlight should be kept away from an enclosed space where people are working.

Closer scrutiny of these provisions first of all makes clear that the very general duty of care in 6.1 (1) does not give a clear threshold value below which the temperature does not cause damage to the health of the workers nor a clear methodology for risk assessment, more particularly on how to establish whether or not the temperature exceeds an Occupational Exposure Limit. Until 2013, the legislation did in fact refer to well established methods, notably ISO 7243 and ISO 7933. The relevant “Policy Rule” 6.1, however, was repealed during an operation to strike all Policy Rules, to make room for ‘tailor made’ regulations in the OSH catalogues—this notwithstanding a science based policy advice by the Health Council of the Netherlands, less than two years earlier, to use an OEL for heat (either the aforementioned ISO standards and/or the NIOSH Recommended Effect Limits (REL))¹⁴⁾.

Second, it is clear that article 6.1 (2) is not in line with the hierarchy of control (STOP-strategy), which favors tackling risks at source over personal protective equipment. In fact, organizational measures such as limiting working times or breaks are also preferred over personal protective equipment. This article is currently being revised as a result of the NLA project as well as the ADAPTHEAT-project.

Third, the provision gives no guidance on what personal protective equipment specifically is suitable, to what extent the duration of exposure should be reduced, or how frequent work should be alternated with breaks or alternative activities in a more moderate environment.

If the legal provisions in the Netherlands are compared with the 10 legislative measures identified by the International Labour Organization (ILO)¹⁵), it is clear that Dutch legislation is clearly lacking in several points (Table 1).

Table 1. Dutch legislation compared to International Labour Organization (ILO) recommendations*.

ILO 2024	Dutch Working Conditions Act (WCA)	Dutch Working Conditions Decree (art. 6.1)
1. Participatory risk assessment in the working environment integrating excessive heat.	Art. 5 WCA (but nothing on participation). MSME’s must also perform risk assessment, but may use specific risk assessment tool for MSME’s. Some of these tools mention ‘involve workers’, but this is not a legal obligation and these tools actually steer away from participation as they are computer based, ‘easy to use’ tick-boxes.	Nothing specific. The Dutch Works Councils Act, however, does bestow a right of approval on works councils concerning the risk assessment. A formal right of approval dose not, however, guarantee participation in the process of risk assessment.
2. Identification of and targeted strategies for worker groups at high risk, including outdoor and indoor workers, those in informal economies and MSMEs, among others.	Very general identification of high risk groups (not specifically on heat).	Nothing specific
3. Use of a heat stress indicator to assess the level of heat exposure, with varying safety thresholds based on work intensity. Note: Specify which method (WBGT or others) and its TLVs.	Nothing	Currently not in the public law provisions. Struck out of the Working Conditions Decree and Working Conditions Rules in 2013.
4. Hydration strategies, including adequate sanitation facilities, especially for female workers.	Nothing	Nothing in article 6.1 (2). Specific provision on sanitation facilities for women struck from Decree in 2013.
5. Rest, breaks or modified work schedules to limit or avoid exposure to excessive heat, including the ability to self-pace.	Nothing in WCA nor Working Times Act	Only very general provision in article 6.1 (2)
6. Provision of cool, shaded and ventilated rest areas.	Nothing	Only general provision in article 6.1 (2)
7. Heat acclimatization measures for workers without recent heat exposure.	Nothing	Nothing specific on acclimatization of workers in article 6.1 (2)
8. PPE designed to protect workers from heat stress.	General obligation to supply PPE’s (art. 3 (1)(b)), free of charge (art. 44).	Very general on PPE’s in 6.1 (2). Technical specifications are part of private (ISO) standards.
9. Education and awareness on heat stress and heat-related illnesses.	General duty to educate workers on health risks in general (art. 8)	Nothing specific in article 6.1 (2)
10. Regular medical check-ups and health monitoring.	General duty to provide health monitoring free of charge (art. 18)	Nothing specific on heat

*ILO (2024), Heat at work: Implications for safety and health A global review of the science, policy. and practice, p. 76. MSME: micro, small and medium sized enterprises; TLVs: threshold limit values.

Social dialogue pertaining to three core elements of OSH legislation

Even if it is the stated regulatory strategy that the general provisions in both the WCA and the WCD should be colored in by means of social dialogue between employers and trade unions (or works councils), it was clear from the beginning that the very general legal provisions leaves the individual employer empty-handed in finding specific, tailor made measures at the company level. Social partners on both the national and sector level were therefore invited to enter into dialogue to flesh out the general legal stipulations in order to assist companies in their search for these tailor-made solutions. The outcome of this social dialogue should then be adopted in the already mentioned OSH catalogues, which also serve as a reference point for public law enforcement by the labor inspectorate.

Over the years, then, social dialogue at the sectoral level should have yielded three forms of tools addressing the core elements in the system of OSH policy: risk assessment (in the sectoral risk assessment tools as well as some of the OSH catalogues), an Occupational Exposure Limit (implicit in both the risk assessment tools and the catalogues, and explicit in some of the collective labor agreements), and specific measures (mainly in the OSH catalogues). In the next section, these three core elements will be explored further.

Findings II: Actual Contribution to ‘Tailor Made’ Solutions for Working in Heat

Risk assessment

Article 5 of the Working Conditions Act requires that the employer perform a risk assessment. It does not specify which risks should be assessed. As hot weather should be considered a risk in nearly every work situation, it is clear that the risk should also be part of all risk assessments performed by employers. Still, it is abundantly evidenced that risk assessments in the Netherlands, in general, are of very poor quality. Half of all companies have not performed risk assessment at all, and in most of the other cases the assessment of relevant risks is sub-standard. For example, when working with dangerous chemicals, the employer should assess the nature, extent and duration of exposure. Research by the Dutch Labor inspectorate found that this is done in just 10% of all companies that work with chemicals (even in case of carcinogens)¹⁶⁾.

The quality of risk assessment in the field of heat exposure has not been researched by the Labor inspectorate. As said earlier, all science based methodologies (WBGT, ISO 7243 and/or the NIOSH Recommended Effect Limits (REL)) were struck from the legislative corpus in 2013, and were to be replaced with clear guidance in either the sectoral risk assessment tools, the OSH catalogue (or, less common, collective labor agreements). Analysis of these three outcomes of social dialogue paints a rather bleak picture: little effort has been taken in social dialogue to fill the legal void left in 2013.

Analysis of 17 risk assessment tools developed under the auspices of Steunpunt RI&E showed that hardly any of those refer to ‘heat’ as a risk. Most of them do mention ‘climate’, but only in very general wordings, referring not to heat but mostly to ‘comfort’, and almost only in the context of indoor situations (offices). Most of these risk assessment tools are of really poor quality. Some are no more than a simple tick box: “is there adequate ventilation? ” (directly leading to the apparent ‘risk measure’ “provide adequate ventilation”, without specifying what ‘adequate’ means). None of the 17 tools identified worker groups at high risk such as pregnant women, workers with medical problems, or workers in the informal economy.

None of the labor agreements give guidance to risk assessment. Also, none of them contained guidance on specific monitoring systems¹⁷⁾.

Of the 60 OSH catalogues studied, roughly half do not at all address that risks should be assessed. No more than 21 do refer to a specific ISO-standard (either ISO 7243, ISO 7933 or ISO 7730)—many of them, however, focusing on process heat rather than climatological heat. Only a very limited number of good examples pertaining to assessing heat were found. Four OSH catalogues referred to continuous measurement, but three of these addressed process heat. Still, the branch organization in the construction industry, being one of the better examples of sector level OSH expert centers, has developed a 50 page guidance on how to assess all forms of heat at work¹⁸⁾.

In sum, most models are not very helpful in performing an adequate risk assessment. At best, they serve to restore what was removed from public legislation in 2013. But for the most part, they steer employers, works councils and OSH specialists away from science based risk assessment approaches.

Still, OSH catalogues or risk assessment tools might be useful in risk communication. Indeed, many of the OSH catalogues do mention some of the risks (Table 2), albeit none of them comprehensively. Also note that the higher percentages in the (+4) cells below were for the most part the result of industrial sectors where process generated heat is an OSH problem, hence not telling anything about climate induced heat. It was found that the OSH Catalogues in the Rubber industry and the Composite industry were literally copied in four other catalogues (Industrial Foam, PVC, Thermoplastics, and Adhesives & Sealants. These have been added as +4 in the Table.

Table 2. Use of occupational safety and health (OSH) Catalogues as a means to raise heat risk awareness.

Possible consequences	Number of times in OSH catalogue(n=56+4)	%
Skin cancer	11	18%
Skin diseases	7	12%
Heat cramps	11 (+4)	25%
Heat exhaustion (shock)/ dehydration	15 (+4)	32%
Heat stroke	13 (+4)	28%
Headache, nausea	4	7%
Kidney failure	2	3%
Eye damage/cataracts	1	2%
Cardiac arrythmias	4	7%
Risk groups (elderly, overweight, pregnant women, users of specific medicines)	7 (+4)	18%
Heat syncope/fainting	11	18%
Occupational accidents	6 (+4)	17%

The communicative value of the OSH catalogues and risk assessment tools, in sum, clearly has not been reaped in full.

Occupational exposure limits, action values

As was mentioned before, until 2013 the Policy Rule 6.1 contained references to ISO standards that could be used to derive an occupational exposure limit or action value. Clearly, with the deletion of the Policy Rule in 2013, there no longer is a clear legal threshold or action value. It was expected that this void would be filled by negotiated, sectoral threshold values. Indeed, in various collective labor agreements, OSH catalogues and risk assessment tools, such values have been found.

Most importantly, action values have been included in some collective labor agreements. Particularly, some collective labor agreements address the concept of ‘unworkable weather’ (or rather ‘extraordinary natural circumstances’). The core of these agreements on ‘unworkable weather’ is that, if it is too cold to work, the work must be terminated but the workers are entitled to full pay. The costs of this interruption of work are partly covered by social security funds. This is guaranteed by public law, more specifically the Unworkable Weather Regulation¹⁹⁾. It is noteworthy, however, that the Regulation itself does not specifically address heat as a matter of ‘unworkable weather’. And nearly all labor agreements on ‘unworkable weather’ too only refer to ‘frost, sleet or snow’ as well as ‘excessive rainfall’. The Guidance on the Dutch unworkable weather regulation²⁰⁾ also mentions storm as a factor, but is silent on heat too. Still, a very limited number of collective labor agreements (n=3) do refer to heat as being a condition to be considered ‘unworkable’. Most importantly, a number of collective labor agreements in the agricultural sector define ‘unworkable weather’ as a ‘heat day’ if:

• 35°Celsius or higher or 5 consecutive days with a daytime temperature of 27°C or higher or 3 consecutive days with a night-time temperature higher than 18°C and a daytime temperature higher than 30°C.

• if the measured temperature between 07:00 and 17:00 has been higher than 35°Celsius or the measured day temperature has been 27°C or higher for 4 consecutive days, or a night temperature of >18°C and a day temperature of >30°C have been recorded for 3 consecutive days, according to the measurement of the KNMI weather station in the postal code area in which the work object, where the employee works or would work.

Note that the stipulations in various collective labor agreements within the same sector do differ (5 vs. 4 ‘consecutive days’, for example). In the construction sector too, some collective labor agreements refer to heat—also with differing action values. Another problematic issue in the second above stipulation is that it refers to the postal code, but that workers may spend the night in different postal code areas, which leaves room for interpretation and legal uncertainty.

More importantly, however, air temperature as such is not a reliable indicator to establish whether it is too hot. All state of art methods in establishing heat also include humidity, wind speed, and the physical effort to be exerted¹⁰⁾. So, the rather coarse approach via air temperature is clearly insufficient. Air temperatures under 35°C may lead to health risks if physically demanding work is performed under humid conditions (which are quite common in the Netherlands). This is an indication that the level of expertise of those involved in drafting the labor agreement is sub-standard (which will also be noted below on OSH catalogues). Note that both the agricultural and the construction sectors are sectors where work is particularly demanding⁷⁾. Furthermore, much of the work is out in the open, which may lead to exposure to solar radiation which is not reflected in air temperature.

Also, the number of collective labor agreements containing stipulations on heat is extremely low, as employers are actively blocking such stipulations to be added to the collective labor agreement—trying to avoid heat induced work breaks, because the costs of interruption due to heat are not covered by the Unworkable Weather Regulation (which means the employer will have to pay the wages out of his own pocket).

Some OSH catalogues too contain stipulations on heat. However, these are no ‘threshold values’ (meaning that work should be interrupted or terminated), but rather ‘action values’—e.g. perform other, less demanding tasks or distribute water. Only three out of all 60 catalogues indicate that work should be interrupted if the temperature exceeds some sort of OEL—Industrial bakeries (which refers to process generated heat), Greenhouses, and Service and repair of mobile equipment.

Four catalogues indicate that the limit of 40°C results entails that “at this workplace an individual worker may work no more than 4 h per day. The remaining hours are worked in a room where it is cooler than 32°C. The latter does not apply when the outside air temperature is above 25°C, nor if different production steps all take place in the same room. If the indoor air temperature at a workplace exceeds 40°C on average on more than 10 d a year between 9 a.m. and 5 p.m., the employer sets up an action plan to reduce this number of days on an annual basis”. These catalogues are an exact copy of one another, applicable to process heat only.

OSH catalogues that do contain ‘action values’ once again mostly refer to air temperatures only, which vary widely—and almost all in the range between 15–26°C, which has little to do with excessive heat but rather with discomfort.

All in all, the OSH catalogues too offer little clarity on what may be considered to be an acceptable (limit) value, nor on what actions/measures should be taken in which situation. This clearly does not fulfil the ambition of OSH catalogues to provide “clarity on techniques and standards” to assess risks and set clear-cut standards on when it is simply ‘too hot’ to work.

The risk assessment tools too only refer to air temperature (if they mention ‘action values’ at all), with just one exception (risk assessment tool for private bus transport, which also refers to humidity).

Preventive measures

If the temperature at the workplace or unfavorable weather conditions may cause damage to employees’ health, the employer must take preventive measures and draw up an action plan (art. 5 Working Conditions Act, art. 6.1 (2) Working Conditions Decree). What these measures should be, is not prescribed by law, but should be fleshed out in OSH catalogues or maybe in Collective Labor Agreements. When taking measures, the employer should, at least according to Article 3 of the Working Conditions Act, follow the hierarchy of control (or STOP-approach as it is often called in the Netherlands: Substitution, Technical measures, Organizational measures, Personal protection).

Collective Labor Agreements

In the analysis of the Collective Labor Agreements, hardly any references to preventive measures were found. The ones that were found, are limited to providing personal protective equipment, and all concerning solar radiation: sunglasses with UV protection; (sun) cap with neck flap to protect against UV radiation; UV protective workwear; provision of sun cream (several construction collective labor agreements). The Labor Agreement for Construction & Infrastructure contains the explicit provision: “The employer provides the necessary personal protective equipment to the employee or makes it available to him. If the employer does not provide PPE’s, the employee is not allowed to work on the construction site. This has no consequences for his salary”.

An interesting, albeit not protective measure, is that three sectors (all in construction) have stipulated that heat related diseases should be considered an occupational accident. The respective Collective Labor Agreements all include the following definition: “Accident [also] includes sunstroke, [freezing] and heatstroke”—the difference between heatstroke and sunstroke being that that latter is caused by excessive exposure to the sun’s rays while heatstroke is a severe case of hyperthermia in which the body temperature rises above 40°C. Being an occupational accident, victims of sunstroke and heatstroke then qualify for financial compensation.

OSH Catalogues

Describing preventive measures that were found in all 56 (+4) OSH Catalogues in detail would go beyond the limits of this paper. The fact-gathering stage of the analysis, which started with cut-and-paste from all catalogues, yielded over 150 pages of material. Here, we draft a picture on a more aggregate level.

First of all, the general picture is that the OSH Catalogues that were analyzed are clearly skewed to measures in the realm of personal protection (Table 3). The STOP-approach (hierarchy of control) is not well-embedded. Also, no OSH catalogues were identified that systematically address the full spectrum of risk management measures—quite the contrary: many OSH Catalogues make a rather haphazard impression, and they are seldom based on a thorough analysis of the factors contributing to risks of working in heat.

Table 3. Types of measures according to the ‘STOP’-approach.

Type of measure		Number of catalogues
‘Substitution’
	Stop/don’t start work	2
	Minimize work	1
Technical measures
	Workplace design/climate system	15
	Air conditioning	12
	Ventilation	16
Organizational measures
	Take weather forecast into account	13
	Tropical work schedule	15
	Job rotation	12
	Extra (drinking) breaks	16
	Provide information on risks of heat	12
	Medical surveillance	6
	First aid measure	3
Personal protection
	Sun cream	19
	Protective clothing	23
	Use of hats, caps (with or without neck flaps)	12
	Supply drinks or ice cream	26

Second, and most importantly, most OSH Catalogues only draft a (more or less comprehensive) list of issues to be tackled, but seldom actually specify how to deal with the general provisions in the legislation—which should actually be the core added value of the catalogue. Most of the provisions in the catalogues are quite general. ‘Ensure adequate ventilation’, without specifying what the ventilation rate or volume should be installed to be adequate. ‘Provide the workers with protective clothing’, without further details of, for example, the required level of thermal insulation (clo-value or reference to ISO-standards) in relation to which level of the WBGT. The more commonly found provision that the employer should distribute sun cream, to give another example, does never indicate how much of this sun cream should be applied or how often.

Third, some of the more detailed provisions were not really evidence based. For example, introducing a break between 12.00–15.00 may be useful to protect against solar radiation, but is not really helpful to protect against heat (which is often highest between 16.00–19.00). Also, contradictory recommendations were found: some catalogues recommend to take in extra salt (“Ensure adequate drinking water and salt”) or give an advise that may be misinterpreted as an advise to do so (“Make sure your body’s salt levels are maintained”), whereas others explicitly warn against the use of salt (“Some companies provide salt tablets on hot days. Using salt tablets is not effective. They worsen thirst. It is better to supplement loss of salts with natural salt from food”.)

In sum, then, many of the catalogues may be helpful in raising awareness of the risks of heat and provide a list of items to be addressed, but often leave the employer (and workers) empty handed on what to do exactly. And this rather negative conclusion is based on the analysis of the OSH Catalogues that have been published. As was indicated earlier, every catalogue has to be submitted to the Netherlands Labor Authority for approval. And in more than half of the cases, the catalogue is either tested negatively altogether (18%) or partly (11%), or withdrawn by the social partners (27%) on the basis of prior comments by the NLA. And after the regulations on the approval by the Labor Inspectorate were tightened in 2022, no new OSH catalogues have been approved.

This is a clear indication that social dialogue does not lead to evidence based and effective risk management measures. It also is an indication that the level of expertise among the OSH specialists that are involved in the process of drafting a catalogue is rather poor.

Discussion

Health and safety policy and legislation in the Netherlands is based on a long standing tradition of ‘conditional self regulation’, where social dialogue at various levels is key. The underlying idea is that ‘conditional self regulation’ and social dialogue, with ‘tailor made’ OSH policies at the shop floor level, were deemed to be more effective than centralized, ‘command and control’ government approaches that were dominant in Europe until the 1970’s²¹⁾. This model of self-regulation, that was introduced in the Dutch Working Conditions Act in 1980 and the EEC Framework Directive 89/391/EEC, stands rather undisputed. More particularly, support remains high for worker participation at the company level, via works councils and staff representation bodies. The works council has had a very prominent role in OSH policy from the very first inception of the Works Councils Act in 1950, and has been strengthened in the early 1970’s. Worker participation at the company level as well as the sectoral level is deemed a cornerstone of the self regulation approach and its promise of tailor made, effective OSH management²²⁾.

However, it may be questioned whether practice indeed delivers on this promise. In fact, it was found repeatedly that it does not. In 1999, Dutch government introduced and funded the development of OSH covenants, the predecessor of the OSH catalogues. Some ten years later, it was found that the covenants yielded almost no effect: “development of health complaints in the covenant and non-covenant sectors is comparable over time”^{23, 24)}. One of the main reasons for this lack of success, according to research, is unwillingness on the employers side to actually negotiate clear-cut measures²⁵⁾. Roughly the same was concluded in a first evaluation of the OSH catalogues, the successor of the covenants: two thirds of all catalogues only contained very general ‘solutions’ such as “devise an OSH policy, use PPE’s, instruct workers on the risks”²⁶⁾. A study, in 2018, by the Labor inspectorate found that nearly two thirds of all employers had never heard of OSH catalogues, and of the remaining third only 56% claim to be ‘fully knowledgeable’ of their contents²⁷⁾. A more recent survey by the Labor inspectorate found that no more than one out of five employers ever made use of the measures that are proposed in OSH catalogues. And given that these catalogues address only a fraction of the relevant risks, the added value of the OSH catalogue should not be overestimated—to put it very mildly. In an advice in 2023, the SER itself concluded that “for the majority of the employers, these tools are of little use”²⁸⁾. Also, earlier research found that the catalogues are “not easy to find” and “not practical enough”²⁹⁾. And in a 2019 evaluation of the OSH system in the Netherlands, it was concluded that “some industries apparently lack sufficient self-organization capacity to implement such an instrument of self-regulation”³⁰⁾.

As concerns the effectiveness of the system, research indicates that occupational health and safety has hardly improved at all since the mid-1980’s, when ‘enforced self regulation’ made its entrance on the European (and Dutch) scene^{16, 31)}.

The findings presented in this paper clearly point in the same direction as the above findings on OSH policy in general. Many employers do not carry out heat risk assessment, and the quality of risk assessment in the field of heat at work is questionable—at least if we look at the quality of the risk assessment tools studied for the ADAPTHEAT project. Also, there is no reliable information on how many companies have actually used the risk assessment tools—let alone how many times this was done in respect to the risk of heat at work due to climate change.

Our findings concerning heat risk management measures too echo the above quote that catalogues only contain very general ‘solutions’ such as “devise an OSH policy, use PPE’s, or instruct workers on the risks”. Furthermore, even in cases that more specific solutions were found, they often are not in line with state-of-the-art risk management measures. At any rate, it is not known how many of the employers actually use the guidance on heat provided by the OSH Catalogue. Given the general findings on the use of catalogues as well as the knowledge at the side of employers, however, it may be surmised that the OSH catalogues hardly play a role in fighting the risks of climate heat at work—let alone if they are effective.

The best way to assess whether or not these measures are actually effective, would be to establish if the number of work related cases of heat induced illnesses or DALY’s, or the number of heat related accidents, is declining. The current data, however, is not useful for baseline measurement. There is very little information of the actual burden of disease among workers. And as ‘exposure to heat’ was only introduced in the National Working Conditions Survey (NEA) only in 2021, it is impossible to indicate whether exposure to heat has diminished over the last few years.

The NEA, however, does give an indication of how many employers actually take measures to ward off heat and if these measures are deemed satisfactory (by the workers). In Fig. 1 it is shown that, in cases that workers indicate that measures are deemed necessary, on average 11% of the employers do not take measures at all if workers are exposed to heat, and another 33% of the workers are indicating that the measures are inadequate (the education sector was added to the figures below, as it stands out as a sector where many workers are unsatisfied with the measures taken by their employer). Once again, it needs to be stressed that it is not possible to distinguish between process generated or climate related heat. But the sectors below are not in the field of process industries, and clearly there is much room for improvement in the field of heat risk management.

Fig. 1.

Nearly half of workers are not satisfied with risk management measures.

Please note that the % are missing in the vertical lines (they should be 20/40/60/80/100).

Unfortunately, the NEA does not distinguish weather induced or process induced heat. More detailed analysis of the NEA-data also indicates that some of the professions within the construction or agricultural sectors also rank high on the basis of working outdoors. Other professions that rank high are postal workers/package delivery and the uniformed professions (police, private security).

Unfortunately, it has not been possible to link these findings on worker satisfaction to the presence and use (or not) of OSH Catalogues or the use of risk assessment tools. So it is impossible to assess the added value of these latter instruments.

These findings give part of an answer to the last, most fundamental question listed above: how does the Dutch system of social dialogue rate on core principles of good regulation, such as legal certainty, legal equality, transparency, efficiency and, most importantly for experts in industrial hygiene, effectiveness?

Effectiveness

As concerns the latter, it was already indicated repeatedly that the strategy of ‘tailor-made’ regulation may not be very effective. At least not in an absolute sense. Whether or not it is relatively more effective than ‘command and control’ approaches is difficult to assess, given the fact that the data needed for such a comparison is lacking.

Legal certainty

As concerns the core principle of legal certainty, it was found that the regulatory approach concerning heat at work does not stand the test. The most important element of certainty—a clear-cut occupational exposure limit—was struck from the public law provisions in 2013, and in various cases is replaced by ill-founded new OEL’s (if any). Also, the “limit values” that were identified, differ among various sectors. This not only may lead to legal inequality (workers in some sectors may be better protected than in others), but also to confusion and legal uncertainty (which limit value actually applies in case of workers from different sectors working side by side at the same location?). Also, the absence of clear cut OEL’s does not help workers to decide when heat at work should be considered an imminent danger as meant in article 8 (3)(b) of Directive 89/391/EEC, which grants workers the right to stop work and/or immediately to leave the workplace and proceed to a place of safety. In Greece, for example, complete work interruption occurs when the WBGT rises above 32.5°C for low-intensity work, 31.5°C for moderate-intensity work, 30.5°C for high-intensity work, and 30°C for very high-intensity work³²⁾. These temperatures are not very common in the Netherlands, but it does happen—particularly because humidity is quite high in the Netherlands during the summer (74–82%)³³⁾. A comparable provision in Dutch legislation (or rather a new EU Directive) would be very helpful for workers to protect themselves or at least call upon the employer with a well-founded appeal to take measures.

Also, the lack of a uniform OEL requires that the labor inspectorate will have to establish which OEL should be used during visits at work sites. The inspectorate then, ironically enough, still refers to the ISO standard that was struck from the Working Conditions Rule in 2013.

Procedural transparency and power relations

Furthermore, the system of negotiating OSH catalogues is not really transparent. The outcome of labor negotiations may sometimes be considered backroom deals, where health and safety is just one bargaining chip in more complicated processes of give and take. This does not really stand the test of transparent regulatory processes. More fundamentally, if establishing minimum requirements is left to negotiations between parties in sometimes very unequal power relations, this may lead to a situation where some workers are much better protected, for example resulting from a strong position of the trade union, than others with weaker or no trade unions³⁴⁾. Still, occupational health is a fundamental right. In 2022, the ILO added ‘health and safety’ to its Declaration of Fundamental Principles and Rights at Work³⁵⁾. Also, the EU Charter of Fundamental Rights as well as the European Social Charter recognized health and safety at work as a fundamental right³⁶⁾.

Leaving a fundamental right, at least at the minimum level, open to the unpredictable outcome of social dialogue may be considered in breach of general principles of good administration³⁴⁾.

Efficiency

Also, it is not really efficient to re-negotiate legal standards at 60 different tables—adding that this number should be a lot higher, since heat at work is a risk that should be tackled in all sectors. Self regulation in numerous sectors leads to, sometimes needless, transactional costs. If the extra costs do not lead to a better (policy) outcome, it could be defended that extra costs are indeed a waste of money and valuable time. And as said earlier, there is little evidence that the policy outcome of decentralized negotiations is indeed better than centralized government legislation.

Adequate expertise

Finally, it was already noted that the level of expertise at the decentralized levels is probably sub-standard. At the sectoral level, many trade union representatives are lacking in knowledge in the field of occupational health and safety, and the OSH units in the overarching trade union federations are severely understaffed. The same goes for worker participation on the shop floor level: many companies do not have a formal works council or other employee representative body³⁷⁾, many works council do not have the required number of members, are lacking in time and expertise³⁸⁾, and some interests are underrepresented by the works council (notably the interests of flexible and migrant workers, that often do the hardest, most sun-exposed work). So the approach is also at odds with the common public law notion of equal and adequate representation of all relevant interests.

In sum then, the current government policy in occupational health and safety does leave room to engage in social dialogue, but regarding extent and quality of social dialogue, this does not per se lead to the desired results.

The need for an EU Directive

As may deduced from the analysis, the Dutch system of social dialogue and tailor-made policy may have a nice ring to it, but in practice it is far from perfect. The findings from the Netherlands may, therefore, be considered evidence on the need for a specific (EU) Directive on working in heat, also called for by the European Trade Union Conference in March 2025³⁹⁾. Even if social dialogue may have its merits, it is clear from the Dutch findings that social dialogue on tailor-made risk management measures should be conducted on the basis of a firm level-playing ground, preferably a science-based OEL. This binding OEL³⁹⁾, as well as a clear methodology to assess whether or not temperature is above the OEL, should not be the outcome of social dialogue at sectoral or even company level, but should be at the heart of a new EU Directive (or, for that matter, of national legislation). Scientific appreciation of OEL’s and the appropriate heat assessment methodologies is rather conclusive, indicating WBGT or ISO 7243 to be state of art¹⁰⁾. Also, it is rather strange that the OEL’s differ even among EU countries³⁵⁾.

It is, then, recommended to enact a science-based occupational exposure limit (as well as a methodology for risk assessment) in public legislation, to provide for legal clarity and certainty, as well as equal protection of all workers.

On this firm basis, some room may be left to tailor-made solutions at the company level. Still, it is advisable that a new Directive should at least contain a technical Annex, like most OSH Directives in the EU, listing the key aspects that should be addressed in heat risk management. Some general guidance is needed on, e.g., working times (tropical schedule), ventilation volume, which PPE’s to use, and health monitoring, according to the STOP-approach. This would clearly help employers in their search for efficient and effective risk management in case of (extreme) climatological heat. Furthermore, there is a need for some form of financial compensation—both for workers and employers—in case of ‘unworkable weather’. If employers will have to pay for heat-induced time off without compensation, this clearly is a motivation to have their workers keep on working even at the expense of their health. Finally, it should be clear that article 8 (4) of Framework Directive 89/391/EEC, which grants workers the right to leave their workstation in case of imminent danger (at no disadvantage because of their action), also applies to situations of dangerous heat at work.

In sum, it should be recognized that heat at work is not just a matter of adequate public policy, but that fundamental workers’ rights are at stake^{36, 40)}.

Conflict of Interest

None.