User Guide to Thresholds and Classification - Environmental ...

149User Guide for Thresholds and ClassificationsNo useable information about an ingredient that is present at concentrations of 1% or greaterWhen there is no useable information about an ingredient and it is present in a mixture at concentrations of1% or greater, the mixture cannot be assigned a definitive LD 50 or LC 50 . The mixture is, therefore, classifiedbased on the known ingredients only, and an additional statement is attached to the classification that ‗xpercent of the mixture consists of a component of unknown toxicity‘.Table 10.2: Conversion from experimentally obtained acute toxicity range values (or acute toxicity hazardcategories) to acute toxicity point estimates for classification for the respective routes of exposureExposure routesExperimentally obtained or derived LD 50or LC 50 range estimateaConverted LD 50 or LC 50bOral (mg/kg bw) 0 < Category 1 5 0.55 < Category 2 50 550 < Category 3 300 100300 < Category 4 2,000 5002,000 < Category 5 5,000 2,500Dermal (mg/kg bw) 0 < Category 1 50 550 < Category 2 200 50200 < Category 3 1,000 3001,000 < Category 4 2,000 1,1002000 < Category 5 5,000 2,500Gases (ppm in air) 0 < Category 1 100 10100 < Category 2 500 100500 < Category 3 2,500 7002,500 < Category 4 5,000 3,000Category 5Vapours (mg/L in air) 0 < Category 1 0.5 0.050.5 < Category 2 2.0 0.52.0 < Category 3 10.0 3.010.0 < Category 4 20.0 11.0Category 5Dust/mist (mg/L in air) 0 < Category 1 0.05 0.0050.05 < Category 2 0.5 0.050.5 < Category 3 1.0 0.5January 2012 EPA0109