User Guide to Thresholds and Classification - Environmental ...

305User Guide for Thresholds and ClassificationsAppendix 19B: Comparison of Hazardous Substances and NewOrganisms Act 1996 and Globally Harmonized System ofClassification and Labelling of Chemicals aquatic hazardclassificationsThe GHS system of aquatic hazard classifications comprises three acute classes and four chronic classes.The Hazardous Substances and New Organisms Act 1996 (HSNO Act) combines these seven classes intofour categories in recognition of the overlap between the GHS classes. The GHS classes and its equivalentHSNO Act category are in Table 19B.1.Table 19B.1: Comparison of HSNO Act and Globally Harmonized System of Classification and Labelling ofChemicals (GHS) aquatic hazard classificationsGHS aquatic classificationHSNO ActequivalentAcute I 9.1AAcute toxicity – all values1 mg/L96-hour LC 50 (for fish)48-hour EC 50 (for crustacea)72- or 96-hour E rC 50 (for algae or other aquatic plants)This class may be subdivided for some regulatory systems to include a lower band atLEC 50 0.1 mg/LAcute II9.1D clause (a)Acute toxicity – all values > 1 to10 mg/L96-hour LC 50 (for fish)48-hour EC 50 (for crustacea)72- or 96-hour E rC 50 (for algae or other aquatic plants)Acute III9.1D clause (a)Acute toxicity all values > 10 to100 mg/L96-hour LC 50 (for fish)48-hour EC 50 (for crustacea)72- or 96-hour E rC 50 (for algae or other aquatic plants)This class may be extended beyond an LEC 50 of 100 mg/L through the introduction ofanother class.Chronic I 9.1AAcute toxicity all values1 mg/L96-hour LC 50 (for fish)48-hour EC 50 (for crustacea)72- or 96-hour E rC 50 (for algae or other aquatic plants)January 2012 EPA0109