The strongest evidence of an increased risk of ML comes from manufacturing workers and pesticide applicators. Further studies will be needed to correlate reliable exposure data within these specific occupational groups with well-defined subtypes of leukemia to refine this assessment.

Current occupational exposure levels to formaldehyde, set to protect against local irritation, should not be adapted.

No abstract

Residual styrene present in polystyrene food packaging may migrate into food at low levels. To assure safe use, safe exposure levels are derived for consumers potentially exposed via food using No/Low Adverse Effect Levels from animal and human studies and assessment factors proposed by European organisations (EFSA, ECHA, ECETOC). Ototoxicity and developmental toxicity in rats and human ototoxicity and effects on colour discrimination have been identified as the most relevant toxicological properties for styrene health assessments. Safe exposure levels derived from animal studies with assessment factors of EFSA and ECHA were expectedly much lower than those using the ECETOC approach. Comparable safe exposure levels were obtained from human data with all sets of assessment factors while ototoxicity in rats led to major differences. The safe exposure levels finally selected based on criteria of science and health protection converged to the range of 90-120 mg/person/d. Assuming a consumption of 1 kg food/d for an adult, this translates to 90 mg styrene migration into 1 kg food as safe for consumers. This assessment supports a health based Specific Migration Limit of 90 ppm, a value somewhat higher than the current overall migration limit of 60 ppm in the European Union.

Although risk assessment, assessing the potential harm of each particular exposure of a substance, is desirable, it is not feasible in many situations. Risk assessment uses a process of hazard identification, hazard characterisation, and exposure assessment as its components. In the absence of risk assessment, the purpose of classification is to give broad guidance (through the label) on the suitability of a chemical in a range of use situations. Hazard classification in the EU is a process involving identification of the hazards of a substance, followed by comparison of those hazards (including degree of hazard) with defined criteria. Classification should therefore give guidance on degree of hazard as well as hazard identification. Potency is the most important indicator of degree of hazard and should therefore be included in classification. This is done for acute lethality and general toxicity by classifying on dose required to cause the effect. The classification in the EU for carcinogenicity and reproductive toxicity does not discriminate across the wide range of potencies seen (6 orders of magnitude) for carcinogenicity and for developmental toxicity and fertility. Therefore potency should be included in the classification process. The methodology in the EU guidelines for classification for deriving specific concentration limits is a rigorous process for assigning substances which cause tumours or developmental toxicity and infertility in experimental animals to high, medium or low degree of hazard categories by incorporating potency. Methods are suggested on how the degree of hazard so derived could be used in the EU classification process to improve hazard communication and in downstream risk management.