Acceptable surface limits (ASLs) of skin sensitizers derived from the local lymph node assay (LLNA): BrdU-ELISA EC1.6 values and their relationships to known sensitization potency information.

ABSTRACT

Skin sensitization is an extremely important risk factor for occupational health and safety, and it would be desirable to set health-based exposure limits (HBELs) for the quantitative risk assessment (QRA) based on the skin sensitizing potencies of chemical. We attempted to set acceptable surface limits (ASLs) as HBELs for skin sensitizers in the workplace based on the local lymph node assay (LLNA) BrdU-ELISA EC1.6 values. To calculate the ASLs, a safety assessment factor (SAF)interspecies value of 6, based on the EC1.6 values/human repeat insult patch test (HRIPT) NOEL ratios, a SAFinterindividual value of 10, and a SAFfrequency/duration value of 3 were applied, referring to previous literatures on SAFs for skin sensitization QRA, and the composite SAF was calculated as 180. The ASLs (mg/100 cm2 ) derived thus for 33 chemicals ranged from 0.001 to 10.417. Comparison of the ranges with known human sensitization potency classes and GHS subcategories revealed that use of GHS Category 1A chemicals needs to be controlled to ensure surface residue levels of less than 1 mg/100 cm2 . To minimize sensitization risks, a quantitative sensitization risk assessment method for chemicals and appropriate risk management are necessary. This report provides a potentially useful ASL-based method of managing sensitization risk derived from LLNA BrdU-ELISA EC1.6 values, comparison of the ASLs and known human sensitization potency data showed that GHS subcategorization results would be a primary information notifying ASL ranges to be required for minimizing the sensitization risk.