Respirable crystalline silica (RCS) is a well-established occupational cause of silicosis and lung cancer. The International Agency for Research on Cancer (IARC) (1) classifies crystalline silica inhaled as quartz or cristobalite from occupational sources as carcinogenic to humans (Group 1). The EU has likewise recognised the carcinogenicity of RCS in Directive 2017/2398 (2), which states that there is “sufficient evidence of the carcinogenicity” of respirable crystalline silica dust and establishes a binding occupational exposure limit (BOEL) of 0.1 mg/m³. Recital 18 of the Directive also provides for the review of this limit, in particular in light of the number of workers exposed.
Already in 2003, the Scientific Committee on Occupational Exposure Limits (SCOEL) (3) concluded that there is no clear threshold for silicosis and that an occupational exposure limit should be below 0.05 mg/m³. Its assessment indicated that exposure at 0.05 mg/m³ could still result in measurable silicosis, while 0.02 mg/m³ was associated with substantially lower predicted prevalence.
More recent evidence however shows that even 0.05 mg/m³ cannot be considered a safe threshold and reinforces the need for continued exposure reduction. The 2024 Health Council of the Netherlands and Nordic Expert Group (4) concluded that there is no safe exposure concentration for RCS below which adverse health effects do not occur. Their risk assessment estimated that at an eight-hour time-weighted average concentration of 0.0363 mg/m³, 40 years of occupational exposure is associated with an estimated excess lifetime risk of four additional lung-cancer deaths per 1,000 workers, while 0.00038 mg/m³ corresponds to four additional deaths per 100,000 workers. These are population-level risk estimates, not guarantees or predictions for individual workers.
1. Immediate reduction to 0.05 mg/m³ with an automatic pathway towards safer BOELs
EFBWW supports reducing the EU BOEL from 0.1 to 0.05 mg/m³ as an immediate and necessary first step, while recognising that significant residual risk remains at 0.05 mg/m³. This is particularly important for construction, where the joint EFBWW-FIEC (5) research project estimates that around 75% of workers exposed to RCS work in the sector.
EFBWW calls for:
• An EU BOEL of 0.05 mg/m³, applicable immediately.
• A mandatory, pre-programmed downward-adjustment mechanism, embedded directly in EU legislation.
• A first reduction to 0.035 mg/m³ after three years, followed by a further reduction towards 0.02 mg/m³ or lower after another three years, where supported by scientific evidence.
• Each step should be informed by updated scientific, technical and implementation evidence, but should not depend on a new political decision to trigger the process.
• In addition, the European Commission should propose an EU-level mandatory obligation for employers to register and maintain records of workers who have been occupationally exposed to respirable crystalline silica (RCS), with exposure records retained for a period of at least 40 years. Member States should ensure the effective implementation and enforcement of this obligation through their national systems. Such long-term registration is essential to ensure that exposed workers can be appropriately followed up and that the long-term health consequences of RCS exposure can be monitored and addressed.
The proposed 0.035 mg/m³ level is broadly aligned with the above-mentioned 2024 Health Council of the Netherlands/Nordic Expert Group assessment, which identifies 0.0363 mg/m³ as corresponding to four additional lung-cancer deaths per 1,000 workers over 40 years, further demonstrating the need to reduce exposure below 0.05 mg/m³. This reinforces that 0.05 mg/m³ is not a safe threshold. Under Article 5(3) and (5)(c) of Directive 2004/37/EC, compliance with the OEL does not remove the obligation to minimise exposure further, wherever technically possible.
2. No additional transition period, with practical support for SMEs
EFBWW rejects any additional transition period. Once the new requirement is transposed, 0.05 mg/m³ must apply immediately. The EFBWW-FIEC joint project shows that effective exposure reduction is technically feasible for most construction activities using prevention methods and equipment already available on the market. Its mapping (6) identifies practical low-dust solutions including wet cutting and drilling, extraction drills and vacuum adapters, local extraction on handheld tools, dust extraction at mixers and bag-opening points, industrial vacuum cleaners, air cleaners, dust barriers and regular dust-free cleaning.
The evidence also demonstrates that how work is performed can make a decisive difference to exposure. For example, the EFBWW–FIEC research reports geometric mean RCS exposure levels during drilling of 0.308 mg/m³ and 1.155 mg/m³ in separate datasets where no extraction was used, compared with geometric mean levels of 0.009 mg/m³ and 0.071 mg/m³, respectively, where extraction was used; air cleaning can reduce exposure further. The EFBWW-FIEC research concludes that, where appropriate protective measures are correctly applied, even the lowest limit values can be achieved for most construction activities. Immediate application should be accompanied by targeted support for SMEs, including:
• financial support for necessary equipment and workplace adaptations;
• practical guidance on low-dust working methods and equipment;
• support for Local Exhaust Ventilation (LEV), wet processes, extraction systems, industrial vacuum cleaners and air cleaners;
• technical assistance where effective solutions remain difficult or are still being developed;
• accessible training and guidance for employers and workers.
Such support must facilitate immediate compliance, not justify delaying it. The EFBWW-FIEC mapping demonstrates that the tools and working methods needed to substantially reduce RCS exposure are already available for most construction activities. Moreover, seven EU Member States (Austria, Belgium, Finland, Germany, Portugal, Slovenia and Spain) already apply an OEL of 0.05 mg/m³, demonstrating that the necessary practices and methods for achieving this level are already in place and can provide a basis for supporting other Member States in lowering their limits immediately.
3. Prevention, worker awareness, training and respiratory protection
Effective implementation requires workers and employers to understand that RCS remains a serious health risk even when dust is not visible, work is routine, or exposure is below the legal limit. Compliance with the BOEL does not mean zero risk or end the obligation to reduce exposure further. Prevention must therefore prioritise technical and collective measures, supported by training and correctly used respiratory protection where necessary.
EFBWW calls for:
• Clear worker information and mandatory practical training for workers, supervisors and employers on RCS risks, dust-generating activities, low-dust methods and control measures.
• Priority for engineering and collective controls, including wet processes, dust suppression, enclosure, Local Exhaust Ventilation (LEV), extraction systems and air cleaning.
• Mandatory fit testing of tight-fitting RPE before initial use and at least annually, together with training on its selection, correct use, maintenance and storage, taking account of face shape, facial hair and worker characteristics, including women and smaller workers.(7)
• Regular exposure monitoring, workplace checks and effective enforcement, particularly where technical controls do not consistently provide sufficient protection.
4. Artificial stone: a high-risk source of RCS
Artificial/engineered stone requires specific attention because it can contain more than 90% crystalline silica, creating exceptionally high RCS exposure during processing. The EFBWW-FIEC research also documents severe silicosis among workers exposed to artificial stone, including after relatively short periods without adequate protection. The risk extends beyond manufacturing to cutting, drilling, installation, repair and removal on construction sites.
EFBWW therefore calls for:
• A clear EU pathway towards the phase-out and eventual prohibition of high-silica artificial-stone products.
• A progressive reduction of permitted crystalline-silica content, starting with a 20–30% threshold, subject to scientific assessment and safer alternatives.
• Requirements covering the entire supply and work chain, from manufacture and supply to installation, processing, repair and removal.
• Specific information, training and prevention measures for workers handling these products.
• Continued monitoring of safer materials and technologies to support further regulatory action.
1 IARC, Arsenic, Metals, Fibres, and Dusts – IARC Monographs, Volume 100C, 2012. Available at: https://publications.iarc.who.int/120
2 European Parliament and Council, Directive (EU) 2017/2398 amending Directive 2004/37/EC on carcinogens and mutagens at work, 2017. Available at: https://eur-lex.europa.eu/eli/dir/2017/2398/oj/eng
3 SCOEL, Recommendation from the Scientific Committee on Occupational Exposure Limits for Silica, Crystalline (respirable dust), SCOEL/SUM/94, 2003. Available at: https://echa.europa.eu/documents/10162/35144386/162_silica_crystalline_oel_en.pdf/1f8c415c-0238-d11d-6cf8-df26ad927131?t=1691407199215
4 Health Council of the Netherlands and Nordic Expert Group, Respirable crystalline silica – Evaluation of health hazards as basis for an occupational exposure limit, 2024. Available at: https://www.healthcouncil.nl/documents/2024/09/10/respirable-crystalline-silica
5 EFBWW and FIEC, Reducing Respirable Crystalline Silica Dust Effectively on Construction Sites, 2021. Available at: https://www.efbww.eu/eu-projects/finalised/reducing-respirable-crystalline-silica-dust-effectively/226-a
6 EFBWW and FIEC, Reducing Respirable Crystalline Silica Dust Effectively on Construction Sites – Mapping, 2022. Available at: https://www.efbww.eu/eu-projects/finalised/reducing-respirable-crystalline-silica-dust-effectively/226-a
7 Health and Safety Executive (HSE), Fit testing basics. Available at: https://www.hse.gov.uk/respiratory-protective-equipment/fit-testing-basics.htm.