Europe Sets First Binding Exposure Limits for Cobalt, PAHs, 1,4-Dioxane and Isoprene
Published on 10/21/2026 at 20:41 | Editorial boerse-global.de
Sweeping new exposure ceilings for four workplace substances — and the formal recognition of welding fumes as a hazard — are now locked in at EU level. The Council of the European Union and the EU governments have adopted the sixth revision of the directive on the protection of workers from carcinogens, mutagens or reprotoxic substances at work (CMRD, 2004/37/EC; Council document PE-CONS 54/26 of 8 October 2026).
The revision introduces binding EU occupational exposure limits for cobalt and its inorganic compounds, polycyclic aromatic hydrocarbons (PAHs), 1,4-dioxane and isoprene. Welding fumes are also officially added to Annex I of the directive. According to the Council's calculations, the measures should prevent around 1,700 cases of lung cancer and roughly 19,000 other work-related illnesses over the next 40 years.
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Cobalt and PAHs get tiered limits
Cobalt and its inorganic compounds will be subject to separate ceilings depending on the dust fraction. For inhalable cobalt dust, the directive sets a limit of 0.01 mg/m³, backed by a six-year transitional value of 0.02 mg/m³. For respirable dust, the EU limit is 0.0025 mg/m³, with a transitional period at 0.0042 mg/m³.
Recital 11 notes that cobalt consumption is expected to rise by 330 percent by 2050 as part of the energy transition.
For PAHs, a limit of 0.00007 mg/m³, measured as benzo[a]pyrene, is being introduced. Nine particularly affected sectors — including steel and iron foundries, aluminium producers, coking plants, tar distillation and rail welding — get a seven-year transitional period with a ceiling of 0.00014 mg/m³.
Rules for 1,4-dioxane, isoprene and welding fumes
For 1,4-dioxane, the amendment sets a long-term limit of 7.3 mg/m³ (2 ppm), a short-term value of 73 mg/m³ (20 ppm) and a biological limit of 45 mg HEAA per gram of creatinine in urine. Isoprene will be capped at 8.5 mg/m³ (3 ppm).
Welding fumes are listed in Annex I, point 9, of the directive but initially receive no numerical limit of their own. Instead, Article 18a(12) obliges the European Commission to assess whether additional limits are needed in future. At the same time, Recital 26 states that statistical data on work-related illnesses are often unavailable, unreliable or inadequate.
Transposition and impact on German rules
Member states have two years to transpose the new EU requirements into national law. The directive enters into force on the 20th day after its publication in the Official Journal of the European Union, though the exact publication date is still open. The multi-year transitional periods for cobalt (six years) and PAHs (seven years) also start from that point.
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In Germany, the directive will require targeted adjustments to the Technical Rules for Hazardous Substances (TRGS 900). For 1,4-dioxane, the existing TRGS 900 workplace limit from March 2023 stands at 73 mg/m³; it is declared in the national rulebook as not health-based and exceeds the future EU long-term value tenfold.
For inhalable cobalt, the existing German limit — following a change in May 2026 — matches the six-year EU transitional value at 0.020 mg/m³, but sits above the permanent target. No separate limit for respirable cobalt currently exists in TRGS 900. For isoprene, the German limit from July 2013, at 8.4 mg/m³ (3 ppm), is already marginally below the new European mark.
