Evaluation of urinary selenium as a biomarker of human occupational exposure to elemental and inorganic selenium.

PURPOSE: Selenium (Se) is an essential trace element, which however, exhibits a narrow safe range of intake. Selenium also occurs at several workplaces, which results in an inhalative selenium exposure of the employees. Thus, an efficient exposure assessment strategy is demanded. The most established parameter, selenium in plasma, mostly consists of protein-bound selenium. This study aimed to investigate urinary total selenium (Se-U) as an additional biomarker of recent human occupational exposure to elemental and inorganic selenium. METHODS: Pre- and post-shift urine samples from employees with exposure to selenium-containing dust were analyzed to total selenium and compared with Se levels in urine samples from controls without occupational exposure to selenium as well as correlated with the recent ambient Se exposure by personal air monitoring. RESULTS: Se-U in post-shift samples was considerably increased compared to the levels in pre-shift samples as well as to the controls. However, Se-U in pre-shift urine was elevated compared to the Se-U in controls too. Se-U in post-shift urine and even better the shift increment in Se-U correlated with the air exposure of the present shift. A rough estimation by Se-U shift increment and external exposure accounted for an inhalative resorption rate of about 1%. CONCLUSION: Our data indicate that Se-U can display the exposure. Pre-shift Se-U levels may be based on previous exposure and indicate a slow urinary elimination kinetics. The results hint for a rather low resorption rate of selenium and inorganic selenium compounds via the lung.

[Rare occupational diseases]. / Seltene Berufskrankheiten.

Rare work-related illnesses do not usually meet the requirements to be recognised and compensated as a legal occupational disease. However, common diseases (e.g. ovarian carcinoma) are sometimes caused by occupational influences (e.g. asbestos), making the occupational disease ovarian cancer caused by occupational exposure to asbestos a rare disease. Since in our modern working world the occupational influences that are harmful to health are decreasing qualitatively (substitutes) and quantitatively (limit values), the diseases they cause are also becoming increasingly rare.

Is ultraviolet exposure acquired at work the most important risk factor for cutaneous squamous cell carcinoma? Results of the population-based case-control study FB-181.

BACKGROUND: Squamous cell carcinoma (SCC) is one of the most frequent types of cancer constituting a significant public health burden. Prevention strategies focus on limiting ultraviolet (UV) exposure during leisure time. However, the relative impact of occupational and nonoccupational UV exposure for SCC occurrence is unclear. OBJECTIVES: To investigate the association between occupational and nonoccupational UV exposure for SCC in a multicentre population-based case-control study hypothesizing that high occupational UV exposure increases the risk of SCC. METHODS: Consecutive patients with incident SCC (n = 632) were recruited from a German national dermatology network. Population-based controls (n = 996) without history of skin cancer were recruited from corresponding residents' registration offices and propensity score matched to cases. Lifetime UV exposure, sociodemographic and clinical characteristics were assessed by trained physicians. Occupational and nonoccupational UV exposure doses were estimated by masked investigators using established reference values. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were assessed using conditional logistic regression adjusting for relevant confounders. RESULTS: Total solar UV exposure was significantly associated with increased SCC. The OR for high (> 90th percentile) vs. low (< 40th percentile) and high vs, moderate (40-59th percentile) occupational UV exposure was 1·95 (95% CI 1·19-3·18) and 2·44 (95% CI 1·47-4·06) for SCC. Adjusting for occupational UV exposure, nonoccupational UV exposure was not significantly related to SCC incidence. Dose-response relationships were observed for occupational but not for nonoccupational solar UV exposure. CONCLUSIONS: Solar occupational UV exposure is a major determinant of incident SCC. Our findings indicate that prevention strategies should be further expanded to the occupational setting.

Sickness absence among peer-supported drivers after occupational trauma.

BACKGROUND: Psychological first aid is a common approach for providing support after potentially traumatic events (PTEs). In Germany, a peer support model is recommended by the German Statutory Accident Insurance (DGUV) to reduce sickness absence after occupational accidents, especially in public transportation. However, data on the effectiveness of peer support are very sparse. AIMS: To analyse whether peer support has an impact on sickness absence after work-related traumatic events in public transportation. METHODS: An analysis was conducted in two German public transportation corporations. Due to ethical requirements, we used a historical cohort study comparing peer support by colleagues (VAG-1), peer support at supervisor level (VGF) and a non-intervention group (VAG-0). The study period was from March 2003 to December 2012. We used a negative binominal regression model to estimate the relative risk associated with the interventions and potential confounders. RESULTS: A total of 259 incident PTEs in employees were observed. A regression analysis identified the severity of PTE (severe and fatal events), VGF and age as significant factors in predicting duration of post-event sickness absence. In a stratified analysis, the mode of peer support (VGF) and age predicted sickness absence for less severe PTEs but this was not significant for severe PTEs. CONCLUSIONS: Severe and fatal PTEs had the strongest impact on sickness absence after PTEs. For less severe PTE, peer support provided by colleagues may be superior to supervisor support.

[Workplace Health Promotion in Small, Medium-Sized and Large Enterprises of the Health-Care Sector - Frequency, Reasons for the Company Management to Take Action and Barriers to Implementation]. / Betriebliche Gesundheitsförderung in kleinen, mittleren und großen Unternehmen des Gesundheitssektors - Häufigkeit, Handlungsgründe der Unternehmensleitungen und Hürden der Realisierung.

PURPOSE: The aim of this study was to gain insight into worksite health promotion in small and medium-sized companies compared to large concerns in Middle Franconia. Action in worksite health promotion, obstacles and demand for networks for workplace health promotion were determined. METHOD: A standardised telephone interview served for collecting data for this cross-sectional study. The interviewee was always the manager or their proxy. 106 companies were contacted. The results of this study were analysed via qualitative and quantitative methods in SPSS(®) 20. RESULTS: It was possible to reach and interview 80 companies, a return rate of 75.5%. More than half the companies (68.8%) implemented at least one activity for worksite health promotion, especially ergonomic measures and measures to promote physical activity. Taking the size of the company into consideration when analysing the results, previous study results are confirmed. With an increasing size of the company, the relative frequency of measures for workplace health promotion rises. The motivation for worksite health promotion ranges from keeping the employees healthy (38.2%) to worksite health promotion as part of the business culture (9.1%). 81.1% of the companies consider their activity in worksite health promotion to be successful. Furthermore, 80.0% of the firms that implemented worksite health promotion were supported by a partner like a health insurance (43.2%). Those companies that did not implement any activities for worksite health promotion, state as a prime reason that they did not think about it as yet (44.0%). Besides, 44.0% of the companies without any worksite health promotion would like to implement measures. 65.5% of the companies that already took action in worksite health promotion and 56.0% of the companies that did not would like to cooperate with other firms in a network for workplace health promotion. Mutual exchange is the most important factor for them. CONCLUSION: The results of this study show that almost half of the companies that did not implement measures for worksite health promotion as yet would like to take action in this regard. For a bigger establishment of worksite health promotion, networks are predestinated and are best accompanied and supported by external professionals like health insurances, mutual indemnity associations or universities.

Occlusive gloves and skin conditions: is there a problem? Results of a cross-sectional study in a semiconductor company.

BACKGROUND: Although there is poor scientific evidence that working with occlusive gloves is as damaging as wet work, prolonged glove occlusion is considered to be a risk factor for developing hand eczema similar to wet work. OBJECTIVES: To assess the effects of wearing occlusive gloves during the whole working day, without exposure to any additional hazardous substances, on skin condition and skin barrier function. METHODS: We investigated 323 employees of a semiconductor production company in Germany: 177 clean-room workers wearing occlusive gloves during the whole shift (exposed group) and 146 employees working in administration (control group). A standardized interview was performed, the skin condition of both hands was studied using the quantitative skin score HEROS, and transepidermal water loss (TEWL) and stratum corneum hydration were measured. RESULTS: There was no significant difference in skin condition between the two subgroups. Values for TEWL and corneometry were significantly higher in exposed participants (P < 0·05). However, the TEWL values were similar to control values if participants took off the occlusive gloves at least 30 min before the measurement. Hence, the effect of occlusion on skin barrier function seems to be transient. CONCLUSIONS: Prolonged wearing of occlusive gloves with clean hands and without exposure to additional hazardous substances does not seem to affect the skin negatively.

Biological monitoring of exposure and effects in workers employed in a selenium-processing plant.

PURPOSE: The aim of the study was to assess external and internal selenium exposure and potential biological effects in employees working in a selenium-processing plant. METHODS: Twenty male employees of a selenium-processing plant (exposed) and 20 age-matched male individuals without occupational selenium exposure (controls) participated in the study. Exposure to selenium at the workplace was determined by personal air sampling. Internal exposure was assessed by measuring total selenium concentration in plasma after a workshift and after holidays as well as by measuring the selenium concentration in urine before and after shift and after holidays. The activity of glutathione peroxidase (GPx) in blood and the prothrombin time were determined as biological effect parameters. RESULTS: The exposure to selenium in the workplace air ranged from 8 to 950 µg/m(3) and exceeded in a large part current occupational exposure limits. The selenium levels in plasma samples of the exposed ranged from 49 to 182 µg/L during exposure and were significantly higher than the plasma levels observed after holidays as well as in the control group. The selenium concentration in pre- and post-shift urine samples did not differ significantly, and the average urinary selenium levels of the employees (18-1,104 µg/g creatinine) were significantly higher than those measured after holidays or determined in controls. Both the concentration of selenium in plasma and in urine did not correlate with the current external exposure of the employees at the workplace. However, we found a strong and significant association between the two biomonitoring parameters. In spite of the considerable high external exposure to elemental selenium, we did not find any effect on the GPx activity in blood as well as on the prothrombin time. CONCLUSIONS: Both the selenium levels in plasma and urine may be used as biological monitoring parameters for the assessment of chronic occupational exposure to selenium. Nevertheless, the toxicokinetics of the urinary excretion of selenium remain still unclear and require further investigations. Moreover, our findings emphasise the necessity of a re-evaluation of occupational exposure limits for elemental selenium and inorganic selenium compounds.

[Psychotrauma after occupational accidents in public transportation. A pilot study to support concepts, influencing factors and occupational health-care]. / Psychische Traumatisierung nach Arbeitsunfällen im öffentlichen Personennahverkehr. Eine Pilotstudie zu Betreuungskonzepten, Einflussfaktoren und arbeitsmedizinischer Versorgung.

BACKGROUND AND AIM OF THE STUDY: Accidents, assaults and suicides occur quite frequently in public transportation. As a result of such extreme events at work, drivers are particularly prone to psychotrauma (PT). Therefore accident insurers stipulate support from the accident site to workplace reintegration with the inclusion of occupational medicine. The present study investigates the incidence, factors influencing psychological trauma as well as the occupational health-care after critical incidents. METHODS: In a Bavarian public transportation corporation 59 employees were evaluated according to ICD-10 for trauma-related disorders, using full collection after application of a specific mental first aid programme and a subsequent occupational health examination. RESULTS: The incidence of PT was 44.1%, with 8.5% showing a post-traumatic stress disorder (PTSD) as consequence of the accident. As significant influencing factors the nature of the accident, the severity of third party injury, and own physical injuries were identified. The occupational medical care depended on the severity of the disease. PT led to the need for rehabilitation. Sick leave was most pronounced in drivers with PTSD. CONCLUSION: The study group showed high levels of emotional strain within the first month. With respect to occupational health-care, particular attention should be paid to drivers after serious accidents or those who sustained own injuries. As foundation for evidence based health-care measures after PT in transport must be scientifically evaluated and the identified risk factors must be well-founded as well.

[Evidence-based health services research--a short review and implications]. / Versorgungsforschung--evidenzbasiert Ein Kurzüberblick und Implikationen.

BACKGROUND: Health services research aims to generate knowledge about care processes of people with illnesses who access health-care services. In addition, the consequences of those processes in the care routine concerning the involved persons and the health system are analyzed. CONCEPT OF THE THEORETICAL WORK: In the first part of the manuscript, an overview concerning the current definitions and subsumptions of the concept of health services research is given. The second part of the manuscript focuses on demonstrating how evidence-based health services research can be used to enable optimization of the care system. The concept is called the "circle of care optimization". In the first step the current care situation concerning its deficits and their reasons is analyzed. In the second step a relevant care goal is defined. In the third step an improvement of an existing care process is developed to achieve the defined care goal. In the fourth step, a comparative empirical study with a high-quality study design is carried out, to assess whether the improved care process is superior to the current care as usual. A health economic evaluation will be performed if applicable. If the results show no or only small advantages, the "circle" starts again with step 3. However, if the results show a significant effect in favour of the new care process and are relevant for the delivery of care and efficient in the context of health economics, a fifth step will be performed which involves developing and testing strategies for implementation. Where relevant, the consequences of implementation are investigated in a sixth step. A "best-practice" practical example is demonstrated to illustrate the "circle of care optimization". CONCLUSIONS: conclusions are derived by illustrating future challenges for health services research.

[Memorandum 'Development of health services research in Bavaria from the perspective of the Bavarian State Working Group 'Health Services Research (LAGeV)': status quo - potential - strategies']. / Memorandum "Weiterentwicklung der Gesundheitsversorgungsforschung in Bayern aus Sicht der Landesarbeitsgemeinschaft Gesundheitsversorgungsforschung: Status quo - Entwicklungspotenziale - Strategien".

The aim of the memorandum on the development of health services research (HSR) in Bavaria is to operationalise the global objectives of the State Working Group "Health Services Research" (LAGeV) and to collectively define future topics, specific implementation steps, methods as well as ways of working for the future course of the LAGeV. The LAGeV is an expert committee that integrates and links the competencies of different actors from science, politics and health care regarding HSR and facilitates their cooperation. The memorandum is based on an explorative survey among the LAGeV members, which identified the status quo of health services research in Bavaria, potential for development, important constraints, promoting factors, specific recommendations as well as future topics for the further development of HSR in Bavaria. From the perspective of the LAGeV members, the 12 most important future topics are: 1) Interface and networking research, 2) Innovative health care concepts, 3) Health care for multimorbid patients, 4)Health care for chronically ill patients, 5) Evaluation of innovations, processes and technologies, 6) Patient orientation and user focus, 7) Social and regional inequalities in health care, 8) Health care for mentally ill patients, 9) Indicators of health care quality, 10) Regional needs planning, 11) Practical effectiveness of HSR and 12) Scientific use of routine data. Potential for development of HSR in Bavaria lies a) in the promotion of networking and sustainable structures, b) the establishment of an HSR information platform that bundles information and results in regard to current topics and aims to facilitate cooperation as well as c) in the initiation of measures and projects. The latter ought to pinpoint health care challenges and make recommendations regarding the improvement of health care and its quality. The cooperation and networking structures that were established with the LAGeV should be continuously expanded and be used to work on priority topics in order to achieve the global objectives of the LAGeV.

[UV-irradiation-induced skin cancer as a new occupational disease]. / UV-Licht-induzierter Hautkrebs als neue Berufskrankheit.

With the revision of the German Ordinance on Occupational Diseases, skin cancer due to UV irradiation was amended as a new occupational disease to the list of occupational diseases in Germany. The new occupational disease BK 5103 has the following wording: "Squamous cell carcinoma or multiple actinic keratosis of the skin caused by natural UV irradiation". Actinic keratoses are to be considered as multiple according to this new occupational diseases if they occur as single lesions of more than five annually, or are confluent in an area > 4 cm(2) (field cancerization). It is estimated that more than 2.5 million employees are exposed to natural UV irradiation due to their work (outdoor workers) in Germany and therefore have an increased risk of skin cancer. In this article the medical and technical prerequisites which have to be fulfilled for this new occupational disease in Germany are introduced.

Extrinsic Notch ligand Delta-like 1 regulates tip cell selection and vascular branching morphogenesis.

RATIONALE: In developing blood vessels, single endothelial cells (ECs) specialize into tip cells that sense vascular endothelial growth factor (VEGF) and contribute to vessel sprouting and branch formation. Tip cell differentiation is inhibited through lateral Notch signaling between ECs, which is controlled by Notch ligands expressed in vessel sprouts. The contribution of the Notch ligand Delta-like (Dll) 1 herein is unknown. OBJECTIVE: To investigate the role of Dll1 in vascular morphogenesis and tip cell formation in the mouse retina. METHODS AND RESULTS: Mice with heterozygous deletion of Dll1 had fewer tip cells during angiogenic sprouting of the superficial vascular plexus but also showed impaired vessel branching into deeper retinal layers and impaired deep plexus angiogenesis. Interestingly, the formation of vertical branches was also guided by filopodia-extending ECs located at the tip of branches, consistent with tip cells, which emerged from established vessels to form a secondary plexus within the deeper neuronal cell layers. During both phases of vascular patterning, Dll1 was not expressed in ECs but in the superficial neuronal layer in close contact with expanding vessels, where Dll1 expression coincided with tip cell formation in a spatiotemporal manner. In vitro, culture of ECs on DLL1 induced essential tip cell genes, including Dll4, VEGF receptor 3, and ephrin-B2, and stimulated VEGF responsiveness and vascular network formation. CONCLUSIONS: Dll1 acts as an extrinsic cue involved in tip cell selection, which directs vessel sprouting and branch formation.

Formation of trinuclear rhodium-hydride complexes [{Rh(PP*)H}3-(µ2-H)3(µ3-H)][anion]2--during asymmetric hydrogenation?

Recently described and fully characterized trinuclear rhodium-hydride complexes [{Rh(PP*)H}3(µ2-H)3(µ3-H)][anion]2 have been investigated with respect to their formation and role under the conditions of asymmetric hydrogenation. Catalyst-substrate complexes with mac (methyl (Z)-N-acetylaminocinnamate) ([Rh(tBu-BisP*)(mac)]BF4, [Rh(Tangphos)(mac)]BF4, [Rh(Me-BPE)(mac)]BF4, [Rh(DCPE)(mac)]BF4, [Rh(DCPB)(mac)]BF4), as well as rhodium-hydride species, both mono-([Rh(Tangphos)-H2(MeOH)2]BF4, [Rh(Me-BPE)H2(MeOH)2]BF4), and dinuclear ([{Rh(DCPE)H}2(µ2-H)3]BF4, [{Rh(DCPB)H}2(µ2-H)3]BF4), are described. A plausible reaction sequence for the formation of the trinuclear rhodium-hydride complexes is discussed. Evidence is provided that the presence of multinuclear rhodium-hydride complexes should be taken into account when discussing the mechanism of rhodium-promoted asymmetric hydrogenation.

Fusion of NUP214 to ABL1 on amplified episomes in T-cell acute lymphoblastic leukemia.

In T-cell acute lymphoblastic leukemia (T-ALL), transcription factors are known to be deregulated by chromosomal translocations, but mutations in protein tyrosine kinases have only rarely been identified. Here we describe the extrachromosomal (episomal) amplification of ABL1 in 5 of 90 (5.6%) individuals with T-ALL, an aberration that is not detectable by conventional cytogenetics. Molecular analyses delineated the amplicon as a 500-kb region from chromosome band 9q34, containing the oncogenes ABL1 and NUP214 (refs. 5,6). We identified a previously undescribed mechanism for activation of tyrosine kinases in cancer: the formation of episomes resulting in a fusion between NUP214 and ABL1. We detected the NUP214-ABL1 transcript in five individuals with the ABL1 amplification, in 5 of 85 (5.8%) additional individuals with T-ALL and in 3 of 22 T-ALL cell lines. The constitutively phosphorylated tyrosine kinase NUP214-ABL1 is sensitive to the tyrosine kinase inhibitor imatinib. The recurrent cryptic NUP214-ABL1 rearrangement is associated with increased HOX expression and deletion of CDKN2A, consistent with a multistep pathogenesis of T-ALL. NUP214-ABL1 expression defines a new subgroup of individuals with T-ALL who could benefit from treatment with imatinib.

Occupational skin cancer induced by ultraviolet radiation and its prevention.

Skin cancer is by far the most common kind of cancer diagnosed in many western countries and ultraviolet radiation is the most important risk factor for cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). Although employees at several workplaces are exposed to increased levels of UV radiation, skin cancer due to long-term intense occupational exposure to UV radiation is often not considered as occupational disease. The actually available evidence in the epidemiological literature clearly indicates that occupational UV radiation exposure is a substantial and robust risk factor for the development of cutaneous SCC and also clearly shows a significant risk for developing BCC. There is enough scientific evidence that outdoor workers have an increased risk of developing work-related occupational skin cancer due to natural UV radiation exposure and adequate prevention strategies must be implemented. The three measures which are successful and of particular importance in the prevention of nonmelanoma skin cancer in outdoor workers are changes in behaviour regarding awareness of health and disease resulting from exposure to natural UV radiation, protection from direct UV radiation by wearing suitable clothing, and regular and correct use of appropriate sunscreens.

[Epidemiology of occupational skin cancer due to UV-irradiation]. / Epidemiologie berufsbedingter UV-abhängiger Hauttumoren.

Skin cancer induced by occupational UV-irradiation is not an official occupational disease number in the appendix of the German ordinance on occupational diseases (Berufskrankheitenverordnung (BKV) but can be recognized as a "virtually" occupational disease according to § 9 (2) of the 7th book of the German Social Code (SGB VII). Epidemiological studies have demonstrated a positive, statistically significant and relevant association between occupational UV-irradiation and the risk of squamous cell carcinoma (SCC) and actinic keratoses (AK). Outdoor workers have on average a 100% higher risk to develop SCC compared to the general population. Therefore, the prerequisites for a new occupational disease are fulfilled and SCC and AK should be reported as an occupational disease if an additional 40% occupationally-related UV-irradiation is documented and the clinical criteria are typical for work- related skin cancer. Epidemiologic evidence also indicates a significant association between work-related UV-irradiation and basal cell carcinoma (BCC) risk: however the results are less consistent and the association is weaker than with SCC. There is an urgent need for further studies in outdoor workers on BCC and lentigo maligna melanoma.

How to quantify skin impairment in primary and secondary prevention? HEROS: a proposal of a hand eczema score for occupational screenings.

BACKGROUND: Skin scoring systems have to meet specific demands depending on their particular settings and indications, e.g. occupational screenings vs. clinical examinations, evaluating progress of treatment or supervision of preventive strategies. Until now, most scoring systems have been developed for severe cases of hand eczema. A validated quantitative scoring system for early hand eczema is still missing. OBJECTIVES: The present cross-sectional study was aimed at assessing the practical value of a quantitative hand eczema score for occupational screenings (HEROS) at the workplace and its potential for identifying individuals at increased risk of work-related skin disease. METHODS: Both hands of 800 male metal workers were examined for characteristic morphological patterns of hand dermatitis and quantified with HEROS. The score was validated by testing inter- and intraobserver reliability in random samples. Results of validation were compared with three already validated skin scores for distinct hand eczema (Osnabrück hand eczema severity index, hand eczema severity index, Manuscore). RESULTS: The score values ranged from 0 to 82 (theoretical maximum 2260), reflecting the skin condition of healthy, fit-for-work subjects. Inter- and intraobserver reliability was good to excellent. Results for reliability of the HEROS were in line with all three validated scores for hand eczema. The predictive value for identifying persons at increased risk for developing hand eczema was low. CONCLUSIONS: The HEROS seems to be an adequate tool for observer near-independent assessment of early hand eczema, especially for quantifying minimal skin impairment. Therefore, we propose the implementation of this scoring system for quantifying early hand dermatitis in occupational screenings.

Does smoking have a significant impact on early irritant hand dermatitis in metal workers?

BACKGROUND: Although they know the long-term complications of smoking, many smokers require additional motivation for entering a smoking cessation programme. At the same time, smoking is considered a possible promoting factor for various skin diseases. OBJECTIVE: The present study assesses the impact of smoking on occupational hand dermatitis in a high-risk population. MATERIAL AND METHODS: 1,355 metal workers, 97.3% of them shift workers, took part in a standardized interview and a dermatological examination of their hands. A subgroup of 1,020 males was willing to be followed-up for 1 year. Of those, 78.3% could be included in the final assessment. RESULTS: Compared to the general German adult population the percentage of smokers was increased (41.7% at baseline). Probably due to self-selection bias and to a higher drop-out rate, the proportion of smokers was significantly lower at follow-up. Compared to nonsmokers, smokers had significantly higher score values for both erythematous lesions and vesicles. CONCLUSION: The present data might give additional support for occupational physicians or dermatologists to convince workers to quit smoking.

Classification of skin sensitizing substances: a comparison between approaches used by the DFG-MAK Commission and the European Union legislation.

A systematic classification of substances (or mixtures of substances) with regard to various toxicological endpoints is a prerequisite for the implementation of occupational safety strategies. As its principal task the "Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area" of the "Deutsche Forschungsgemeinschaft" (DFG-MAK Commission) derives and recommends maximum workplace concentrations and biological tolerance values (MAK and BAT values) based exclusively on scientific arguments. Several endpoints are evaluated separately in detail, e.g. carcinogenicity, risks during pregnancy, germ cell mutagenicity or contribution to systemic toxicity after cutaneous absorption. Skin- and airway sensitization is also considered; the present paper focuses on these two endpoints.