Expert forecast on emerging chemical risks related to occupational safety and health
by
European agency for safety and health at work, 2009
The Community strategy on health and safety at work 2002-2006 called on the European Agency for Safety and Health at Work to ‘set up a risk observatory’ to ‘anticipate new and emerging risks’. Within this context, a series of four expert forecasts were formulated with the aim of providing as comprehensive as possible a picture of the potential emerging risks in the world of work. Three reports on emerging physical risks, biological risks and psychosocial risks have already been published. This publication (the last one of the series) presents the results of the forecast on emerging chemical risks related to occupational safety and health based on an expert survey and a literature review.
Method
Within the scope of this project, an ‘emerging occupational safety and health (OSH) risk’ has been defined as any occupational risk that is both new and increasing.
By new it means that:
• the risk was previously unknown and is caused by new processes, new technologies, new types of workplace, or social or organizational change; or
• a longstanding issue is newly considered as a risk due to a change in social or public perceptions; or
• new scientific knowledge allows a longstanding issue to be identified as a risk.
The risk is increasing if:
• the number of hazards leading to the risk is growing; or
• the likelihood of exposure to the hazard leading to the risk is increasing (exposure level and/or the number of people exposed); or
• the effect of the hazard on workers’ health is getting worse (seriousness of health effects and/or the number of people affected).
To formulate this expert forecast, a questionnaire-based survey was run in three consecutive rounds following the Delphi method. This method was chosen to avoid individual, non-scientifically founded opinions and to verify whether a consensus was reached among the respondents; 174 experts in the first survey round and 152 experts from each of the second and third rounds were invited to participate in the survey following their nomination by the Agency’s Focal Points and Topic Centre Research.
Thirty-one valid questionnaires from the first round, 35 from the second round and 49 from the third were returned from 64 organizations covering 19 European Member States as well as Iceland and Switzerland. The response rates were 31% (first survey round), 35% (second round) and 32% (third round). Participating experts were required to have at least five years’ experience in the field of OSH and chemical risks. The majority of respondents were managers in an OSH organization, or OSH researchers.
Top Emerging Risks
Particles
Among the ‘top ten’ emerging risks, three (nanoparticles and ultrafine particles, diesel exhaust and man-made mineral fibers) have in common their physico-chemical state as particles. According to the Fourth European Working Conditions Survey[1]19.1% of the EU-27 workforce reported in 2005 that they ‘breathe in smoke, fumes, powders or dust’.
The risks posed by ‘nanoparticles and ultrafine particles’ are by far the strongest agreed as emerging by the experts. Applications of nanotechnology are mainly found in:
• information and communication technologies;
• environmental and energy technologies;
• transport, aviation and space;
• agriculture and nutrition;
• medical applications;
• cosmetics;
• military technologies.
The nanotechnology industry is expected to grow rapidly into a global, multi-billion euro market and to employ 10 million workers worldwide by 2014. However, very little research has been performed on the health and safety effects of nanoparticles (NPs). NPs can have very different properties from the same materials at the macro scale. There are indications that the toxicity of particles increases with decreasing diameter and increasing surface area, thus challenging current mass-based risk evaluation approaches. Several studies indicate that, once in the body, NPs can translocate to organs or tissues distant from the portal of entry. Durable, biopersistent NPs may bioaccumulate in the body – in particular in the lungs, the brain and the liver. Ultrafine particles have been found to act as an important environmental risk factor for cardiopulmonary mortality and there is considerable evidence that some NPs are toxic to human health. The basis of toxicity is not fully established, but appears to be primarily expressed through an ability to cause inflammation. NPs could also act like haptens to modify protein structures, hence raising the potential for autoimmune effects. Damage to the cells through oxidative stress, believed to induce many diseases such as cancers, is also suggested. However, decisive scientific information is still lacking.
Although the quantitative data needed for satisfactory risk assessment are still missing, sufficient information is available to begin preliminary assessment and to develop interim working practices to reduce workplace exposure. The manufacturing phase of nanomaterials as well as maintenance and clean-up of equipment used to produce NPs are known to be a source of exposure. Further research should concentrate on the complete life-cycle of a given nanomaterial in order to identify all exposure situations and the workplaces concerned. In parallel, further research should be undertaken to guarantee the development of ‘responsible’ nanotechnology which integrates health and safety considerations.
Exposure to diesel exhaust is the second most emerging risk highlighted in the forecast. According to the CAREX (CARcinogen EXposure) database[2], at the beginning of the 1990s, 3.1 million workers in the EU-15 were exposed for at least 75% of their working time to diesel exhaust, making it the fourth most common carcinogen found in the workplace after solar radiation, tobacco smoke and crystalline silica.
Hazardous levels of diesel exhaust can be found in occupations ranging from mining to driving diesel-fuelled trucks or forklifts. Diesel exhaust is made up of a complex mixture of thousands of fine particles, gases and vapours. The major components are carbon dioxide, carbon monoxide, nitrogen dioxide, nitric oxide, particulate matter and sulphur dioxide. Diesel engine exhaust is classified as ‘probably carcinogenic to humans’ (Group 2A) in the International Agency for Research on Cancer’s classification[3].
More specifically with regard to lung cancer, a positive association between diesel exhaust emissions and lung cancer is suspected but is still controversial. A link between emissions from diesel-fuelled engines and non-cancer damage to the lung has also been found. More research is needed on the health effects of such particulates.
Man-made mineral fibers are divided into siliceous and non-siliceous. Fibers with a geometric diameter less than 3 μm may reach the alveolar zone of the lungs. While the size of the fibers is acknowledged to be linked to their harmful toxic effects (the longer and thinner the fibers, the more dangerous they are), standard air sampling methods do not allow precise measurement of fiber size. Specific fiber dimensions hypothesized to have a biological activity have been proposed but need to be evaluated in epidemiologic studies. In general, fibrous structure increases inflammatory, cytotoxic and carcinogenic potential. Oxidizing stress of the cells can also occur, especially in the case of repetitive exposure.
Manufacturers continuously strive to reduce the biopersistence of siliceous fibers by modifying their compositions – a process favorable to occupational health. However, the compositional changes make it more difficult to obtain comparable data from epidemiological studies. As a consequence, very few toxicological data are available for these new products. Aluminium silicate wool (ASW) – more commonly called refractory ceramic fibers (RCFs) – is carcinogenic category 2 in the EU classification.
ASW/RCF products put on the market are labelled according to Directive 67/548 for substance and preparations. According to the European Ceramic Fibers Industry Association (ECFIA), the manufacturing industry also labels articles containing ASW/RCFs (though not required by the regulations). However, a study by the French agency Afsset found:
• there is no specific code or labelling clearly indicating their presence in items and equipment;
• RCFs cannot be reliably differentiated from other fibers by simple visual examination.
The Afsset survey also found that some companies claim to be unaware of the exact nature of the fiber-containing components they order from their providers and most of them do not carry out any measurements to evaluate the level of workers’ exposure to RCFs. The results of many exposure measurements carried out by producers and prevention organizations are available and could be a help to these companies.
Continuous filament fibers, which are unclassified in the EU classification of carcinogens, have been little studied and there is a need to acquire knowledge on their toxicity. There is also a particular lack of information on special purpose glass fibers. As for carbon fibers, some information inclines towards caution because of their capacity to break and to create ultrafine particles. There are few toxicological data on tungsten oxide and magnesium sulphate whiskers, or on alumina fibers, while silicon carbide whiskers appear carcinogenic in animals. Potassium titanate fibers are suspected to be carcinogenic. The toxicity of other non-siliceous man-made mineral fibers has been little investigated, but they seem to be biopersistent.
Although some man-made mineral fibers contain up to 25% additives, studies rarely take their presence into account. Workers handling fiber-based products, especially during laying, maintenance or removal operations, may be highly exposed.
Allergenic and Sensitizing Agents
Another three risks identified as emerging were mentioned by the respondents with a view to allergies and sensitizing effects. These are epoxy resins, isocyanates and dermal exposure.
Epoxy resins are one of the most important and widely used polymeric systems. They are used in adhesives, sealants, inks, varnishes and reinforced polymer composite structures with glass fiber, carbon fiber or metal substrates, paints and coatings, including protective coatings of canned food. The continuous demand for always newer generations of epoxy resins and derived products with enhanced properties may introduce new, unknown adverse health effects. These effects may be caused by uncured epoxy resins or by the variety of curing agents, diluents or other constituents used in epoxy formulations. Epichlorohydrin, used to obtain epoxy resins, is classified as ‘carcinogenic category 2’ in the EU classification. Bisphenol A, the other coupling constituent, was found to induce allergic contact dermatitis (ACD) and to be a weakly estrogenic monomer.
Epoxy resins themselves have become one of the main causes of occupational ACD. Skin sensitisation of the hands, arms, face and throat as well as photosensitisation has also been reported. Some of the components can also cause irritation of the eyes and respiratory tract, contact urticaria, rhinitis and asthma. Workers in the production of epoxy resins and workers in the manufacture of composite products, in the electrical and electronics industry, and painters may be at risk. Epoxy skin sensitization is particularly problematic in the construction industry where a safe and healthy working environment (e.g. clean room) and the use of protective clothing (e.g. gloves) is less common and/or less practical. Wherever possible, one-part instead of two-part epoxies should be used to reduce the risk of dermal contact during hand mixing. Contact with incompletely cured epoxy resins should be avoided. The proper identification of the epoxy system involved in the process is essential for the selection of appropriate prevention measures.
A further emerging chemical risk identified in the survey is the increasing use of isocyanates. Again exposure to isocyanates does not only occur at the production stage but also when polyurethane products containing isocyanates are used (e.g. when spraying), are processed (e.g. grinding or welding), or when they undergo thermal or chemical degradation. Isocyanates are widely used in the manufacture of flexible and rigid foams, fibers, elastomers, building insulation materials, paints and varnishes. Workers in car body repair shops may, for example, be exposed during the abrasive process of a car body, as isocyanates may be released into the air as a consequence of thermal degradation of the isocyanate-containing car paint induced by the heat generated in the abrasion.
Isocyanates are powerful irritants to the mucous membranes of the eyes and of the gastrointestinal and respiratory tracts. Direct skin contact can cause serious inflammation and dermatitis. They are also powerful asthmatic sensitizing agents. Death from severe asthma in some sensitized subjects has been reported. Early recognition of sensitization, coupled with prompt and strict elimination of the source of exposure, is essential to reduce the risk of long-term or permanent respiratory problems in sensitized workers.
Dermal exposure is a major route of occupational exposure to dangerous substances. In EU Member States, skin diseases are the second most common occupational diseases after musculoskeletal disorders (MSDs); contact dermatitis being the most common. Other work-related skin diseases include chemical burns, contact urticaria, photodermatitis, contact leukoderma (Vitiligo), infectious dermatitis and skin cancer.
Chemicals are responsible for 80–90% of skin diseases. The skin of the hands and other body parts can be affected by indirect exposure to airborne substances (e.g. face, neck) or when contaminated hands touch other body parts (e.g. hand-to-face contact). In the construction industry, chromate is the most important allergen followed by epoxy resins and cobalt. Natural rubber protein (latex) is another major occupational allergen, in particular in the healthcare sector. Soaps, detergents and solvents can cause dermatitis as they remove the surface lipids and dissolve the natural protective barrier of the skin. Allergies from exposure to fragrances have been observed among masseurs, physiotherapists and geriatric nurses. The use of protective gloves is controversial due to other influencing factors such as the wet atmosphere inside the glove.
There are no ‘dermal OELs’. Two reasons are the uncertainties in the quantification of the dermal exposure level and the meagre toxicological data available on health effects from dermal exposure – especially for repeated exposure, exposure to diluted preparations, and combined exposures to various chemicals or to other factors such as humidity. Within the European project RISKOFDERM, determinants of dermal exposure, exposure control measures and default dermal exposure values particularly useful to small and medium enterprises (SMEs) have been defined and integrated into a risk assessment toolkit.
Sector Specific Chemical Risk
Other major emerging risks identified are specific to certain workplaces; for example the exposure to dangerous substances during waste treatment activities and in the construction industry. It is interesting to note that these jobs are neither in the chemical industry nor in industries where chemicals are used intentionally in the work process, but rather where dangerous substances are incidental products of the work.
Dangerous substances in waste treatment activities were also agreed as emerging risks in another expert survey on emerging biological risks[4]. Waste management is considered one of the most hazardous occupations with an illness rate 50% higher and an infectious diseases rate six times higher than in other workers. European and national waste regulations were adopted in the 1990s primarily for environmental purposes (i.e. to reduce the volume of waste sent to landfill) and, as a consequence, do not integrate OSH aspects enough. The amount of waste generated in the EU is growing. Municipal solid waste (MSW) accounts for a relatively small proportion of total waste, with the largest volume of waste being generated by mining, manufacturing, construction and demolition activities.
Up to 110 different volatile organic compounds (VOCs) have been found during waste collection and at compost plants, landfills and resource recovery plants. Landfill workers, compost workers and waste collectors are also exposed to high levels of dust. While an increase in the recycling of car components, plastics and electronic products is expected, there are concerns that waste electrical and electronic equipment (WEEE) and end-of-life vehicles (ELVs) contain hazardous materials such as lead, cadmium, mercury and polychlorinated biphenyls (PCBs). In incineration processes, the pollutants most often detected are dioxins, furans and PCBs. The handling of medical waste presents extra challenges such as the risk of contamination with sharps.
The health effects depend on the type of waste and substances. While it is not possible to completely eliminate the chemical risks inherent to waste-related activities, the most efficient prevention measure is to reduce the generation of dust, bioaerosols and VOCs in the workplace. Technical collective prevention measures and hygiene plans also contribute greatly to reducing workers’ exposure. In any case, prevention should be adapted to the specific characteristics of each branch of the waste sector and its activities.
The construction sector is one of Europe’s largest industries. Construction workers are exposed to a variety of dangerous substances in addition to noise, vibrations, falls from height and musculoskeletal disorders. Respiratory problems are widespread, not least due to asbestos – although its use is now virtually banned in the European Union. If inhaled, asbestos fibers can have serious health effects including asbestosis, lung cancer and mesothelioma. There is no known safe exposure level to asbestos. The more one is exposed, the greater the risk of developing an asbestos-related disease. As the time between exposure to asbestos and the first signs of disease can be as much as 30 years, the effects of past exposure are only now apparent and are still expected to rise[5].
Construction workers may also be exposed to dust generated from cutting or handling crystalline silica-based products. A major effect in humans of the inhalation of respirable crystalline silica is silicosis. Crystalline silica is also classified as ‘Group 1 human lung carcinogen’ in the International Agency for Research on Cancer’s classification. There is currently no Occupational Exposure Limit (OEL) for respirable crystalline silica at an EU level and existing national OELs vary. A European multi-sector agreement aims to reduce workers’ exposure to crystalline silica dust through good practice in the workplace.
Carpenters, in particular, are exposed to wood dust and thus have an elevated risk of contracting nasal cancer. Workers in the construction industry are also exposed to solvents, oils, resins and cement-based products containing chromium (VI) which exacerbate the likelihood of skin problems. Important contact with lead may also occur when working with old lead piping or removing lead-based paints.
Chemical Risks Combined with Organizational Factors
Last, but not least, some of the main emerging risks identified are a consequence of the combination of chemical hazards and poor organizational factors as demonstrated by the selection by respondents of the items ‘poor control of chemical risks in small and medium enterprises’ and ‘outsourced activities performed by subcontracted workers with poor knowledge of chemical risks’.
Micro-, small and medium-size enterprises (SMEs) are socially and economically important, representing 99.8% of all enterprises in the EU-25 in 2003. SMEs employ 66% of the workforce in the private sector. They often experience difficulties in complying with their obligation to assess and control chemical risks in the workplace as laid down by EU Framework Directive 89/391/EEC and Directive 98/24/EC on chemical agents.
In some cases, underlying factors are the limited technical expertise of SMEs and the absence of a dedicated OSH professional. Most SMEs are aware of the hazards associated with the hazardous substances they use but often only in very general terms. Moreover, there is generally a high level of acceptance of the risks as being part of the job. Even when hazardous substances are monitored, the results are not always representative of the actual exposure in the workplace. Despite being feasible in many cases, the possibility of eliminating or substituting the hazardous substance is generally not given enough consideration. While appropriate effective local ventilation is often lacking, there is an excessive tendency in SMEs to rely on personal protective equipment (PPE). In general, workers are not consulted enough about the implementation of controls on hazardous substances.
As the cost of implementing controls is also one of the main barriers cited, one of the challenges is to make OSH a benefit for SMEs. It is essential to target awareness-raising interventions at SME managers as they play a key role in determining the priority for implementing controls. Although SMEs see the distinctions between health, safety and environment as irrelevant to them, they do want to know exactly how to control chemicals in order to meet all regulatory requirements. A number of easy-to-use tools are available but they need to be better shared among the Member States and to be made available to SMEs in their national language.
The item ‘outsourced activities performed by subcontracted workers with poor knowledge of chemical risks’ – such as cleaning and maintenance activities – reflects the increasing concern for multiple occupational risk factors and the importance of taking a holistic approach when managing OSH risks. In particular, outsourcing and subcontracting practices have increased during the last 15 years. Subcontracted workers increasingly perform high-risk work across many industries. They generally have less control over working times, often work in less skilled jobs, have fewer opportunities for training and life-long learning, and subsequently less insight into their work environment. All this contributes to making outsourced workers more vulnerable to OSH risks. Outsourcing practices are also often associated with an unclear repartition of legal responsibilities between the host company and the contractor. There is evidence that these new forms of employment have serious negative effects on workers’ health and safety.
[1]Parent-Thirion, A., Fernandez Macias, E., Hurley, J., Vermeylen, G., Fourth European Working Conditions Survey, European Foundation for the Improvement of Living and Working Conditions, Luxembourg, 2007. http://eurofound.europa.eu/pubdocs/2006/98/en/2/ef0698en.pdf
[2] Kauppinen, T. et al., CAREX – International Information System on Occupational Exposure to Carcinogens. Occupational exposures to carcinogens in the European Union in 1990-1993, Finnish Institute of Occupational Health, Helsinki 1998. http://www.ttl.fi/NR/rdonlyres/4444380F-B1FB-4D01-A974-0B6A9E663CFA/0/1_description_and_summary_of_results.pdf
[3] http://monographs.iarc.fr/ENG/Classification/crthgr02a.php
[4]European Agency for Safety and Health at Work, Expert forecast on emerging biological risks related to occupational safety and health, Office for Official Publications of the European Communities, Luxembourg, 2007. http://riskobservatory.osha.europa.eu/risks/forecasts/biological_risks/
[5] European Agency for Safety and Health at Work, Asbestos in construction. Factsheet 51, Office for Official Publications of the European Communities, Luxembourg, 2004. http://osha.europa.eu/en/publications/factsheets/51/view
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