Well-founded risk assessments are a cornerstone in risk management aimed to protect human health. It lies in the interest of society to use all available toxicological data to the fullest. However, several investigations report that financial interests affect research and risk assessment, one striking example being tobacco products. The evidence in such investigations have to a large part drawn on internal documents from the interested party. However, these kind of source materials are not always available for external scrutiny. A major issue is thus how to identify, investigate and quantify potential influence from special interests across a broad range of substances or risk assessments. In the present study, we used the overall uncertainty factor (UF) as a basis for quantification and comparison across all risk assessments from the European Commission’s Scientific Committee on Occupational Exposure Limits (SCOEL). For each risk assessment/chemical, we compared the UF with various aspects expected to influence its magnitude. Our premise was that the influence could be toxicological (e.g. use of animal vs human data as a starting point for derivation of the exposure limit) as well as from vested interests (e.g. expectation of economic or other benefit). We found several expected correlations with the type toxicological data, for instance lower UFs when human rather than animal data were used (p<0.0001, ANOVA on log-transformed values). We saw no effect of peer-review, funding or origin of data. However, high tonnage substances (tonnes/y produced in or imported in the European Union) had statistically significantly lower UFs (p=0.02). There was also a significant change in the magnitude of UFs between SCOEL mandate periods (p=0.02), indicating influences from SCOEL individual experts and/or a shift in attitudes towards UFs. Although the study is limited to risk assessments performed in one committee, it seems that there are factors beyond the expected scientific aspects that influence the magnitude of the UFs and, hence, the exposure limits.