DFG Commission revises workplace chemical exposure recommendations

The Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has changed its risk-assessment recommendations for ten substances, added three substances and revised six biological limit values in its latest annual review of workplace chemical hazards. The German research foundation DFG submitted the recommendations to Germany’s Federal Ministry of Labour and Social Affairs in July 2026. These are scientific recommendations rather than statutory workplace regulations: the ministry’s Committee on Hazardous Substances first assesses them, after which regulations may be drawn up where necessary.

The commission’s recommendations support implementation of Germany’s Hazardous Substances Ordinance and cover airborne workplace limits, biological monitoring values and biological reference values. The revised assessment of manganese and its inorganic compounds was among the ten changes made to current airborne exposure recommendations. Drawing on evidence from several commission working groups, the commission concluded that exposure to 0.05 mg of manganese per cubic metre of air is not expected to cause adverse health effects.

Manganese is especially relevant to metalworking because welding can generate dusts and fumes containing very small manganese particles. After absorption through the alveoli of the lungs, such particles can be distributed throughout the body and accumulate in the brain, where they can produce neurotoxic effects. For the manganese reassessment, the commission assessed 50 new studies.

These included large epidemiological cohort studies from Australia, South Africa and the United States, together with magnetic resonance imaging examinations of affected brain regions. Christoph van Thriel, head of the commission’s Working Group on Neurotoxicity and Sensory Systems and professor of neurotoxicology and chemosensory research at the Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund University, said the studies were systematically compiled, correlated and evaluated in accordance with the commission’s assessment criteria. The evidence review combined epidemiological observations with brain imaging, supporting the commission’s scientific evaluation of airborne manganese exposure.

The commission’s annual List of MAK and BAT Values, now available in English, brings together recommendations for limiting hazardous exposures in occupational settings. A MAK value, or maximum workplace concentration, specifies the concentration of a substance in workplace air that is not expected to cause long-term harm when present as a gas, vapour or aerosol. The list also includes biological values derived from measurements in blood or urine.

These measurements allow occupational physicians and toxicologists to assess individual exposure resulting from contact with workplace substances. The recommendations therefore address both what may be present in workplace air and what has been absorbed by an exposed person. A biological work substance tolerance value, abbreviated BAT, corresponds to the concentration of a substance or its metabolites in blood or urine that a person can be exposed to throughout a working life without adverse health effects.

The list also contains biological reference values, known as BAR, which can be used to assess the extent of occupational exposure. The commission revised biological tolerance values in blood or urine for six substances in this year’s list, including sevoflurane, inorganic lithium compounds and strontium. These are values for assessing exposure through biological monitoring, and their use in occupational medicine is based on the scientific evaluation for the individual substance.

Three substances were newly added to the list of recommendations: benzophenone, melamine and p-toluenesulfonic acid. Benzophenone is used as a photoinitiator in the printing industry, in chemical synthesis and as a fragrance ingredient in cosmetic products. Melamine is used in the manufacture of melamine resins, which are employed in plastics and adhesives.

The newly established BAT value of 300 µg melamine per litre of urine provides a health-based reference value for assessing exposure in people who have absorbed melamine. This is an individual biological monitoring value rather than a new general limit on melamine in workplace air. For p-toluenesulfonic acid, described as a strong acid, the commission derived a MAK value of 0.2 mg/m³.

The compound is used as a catalyst in chemical synthesis, as a curing agent and as a descaling agent. Its addition therefore brings the substance into both the airborne exposure and occupational-health assessment framework maintained by the commission. As with the other entries, the values are accompanied by detailed scientific justifications, allowing readers to examine the evidence and the assessment methods used for the substances reviewed.

The complete documentation and method descriptions are available through the commission’s MAK Collection. The proposed amendments and new additions remain open for discussion until 31 December 2026. During that period, new data or scientific comments may be submitted to the commission.

This consultation period is part of the commission’s process for keeping its recommendations current with scientific findings. The open review does not itself create binding workplace rules, nor does it determine whether regulations will be adopted. Instead, the recommendations proceed through the stated regulatory route: initial assessment by the Federal Ministry of Labour’s Committee on Hazardous Substances and the drawing up of statutory regulations where necessary.

Over the past year, the commission published 70 outputs, including 40 MAK documentation reports, 10 BAT documentation reports, 10 descriptions of air-monitoring methods and 10 biomonitoring methods. Andrea Hartwig, commission chair and professor at the Karlsruhe Institute of Technology, said the publication volume reflected the voluntary commitment of scientists working together across disciplines within the commission. International access to the commission’s work has also increased.

Since spring 2026, new publications from the Permanent Senate Commission have been indexed in the US National Library of Medicine databases PubMed and PubMed Central. Hartwig said the inclusion reflected the quality and relevance of the commission’s work for evidence-based occupational health and safety worldwide. Substance documentation reports and method descriptions are available in the MAK Collection, while the commission’s other publications are available on an open-access basis so that the knowledge can be reused for scientific purposes.

The 2026 list thus combines reassessed exposure evidence, revised biological monitoring values, new substance entries and expanded access to the supporting scientific and methodological material.

Subject of Research: DFG assessment of occupational exposure limits and biological monitoring values for workplace chemicals

Article Title: Health and safety at work: DFG Senate Commission assesses the risk of chemical compounds

Article References: Health and safety at work: DFG Senate Commission assesses the risk of chemical compounds. Original publication (Bibliographic details unavailable.)

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Keywords: occupational health, workplace exposure limits, hazardous chemicals, manganese, biological monitoring, welding fumes, neurotoxicology, chemical risk assessment, DFG, toxicology, Health, safety