User Guide to Thresholds and Classification - Environmental ...

137User Guide for Thresholds and Classifications(B) 20 milligrams or less of the substance per litre of air, if the substance is avapour; or(C) 5 milligrams or less of the substance per litre of air, if the substance is a dust ormist; or(c) clinical signs (other than diarrhoea, piloerection, or an ungroomed appearance) indicateto an expert a significant adverse biological effect as a result of acute exposure ofanimals by—(i) oral or dermal routes to 2000 milligrams or less of the substance per kilogram ofbodyweight; or(ii) the inhalation route to—(A) 5000 parts or less of the substance per million in air, if the substance is a gas;or(B) 20 milligrams or less of the substance per litre of air, if the substance is avapour; or(C) 5 milligrams or less of the substance per litre of air, if the substance is a dust ormist; or(d) reliable information for the substance, including reliable information from animal studiesother than those from which LD50 data was obtained, where exposure was by a routeother than oral, dermal, or inhalation, indicates to an expert the potential for significantacute toxic effects in humans after exposure to the substance; or(e) data for the substance, in the opinion of an expert, indicates evidence in humans ofsignificant acute toxic effects as a result of exposure to the substance…(2) A substance is not required to be tested in accordance with subclause (1)(a) if thesubstance—(a) has been tested in accordance with subclause (1)(b); and(b) does not meet the minimum degree of hazard specified in subclause (1)(b).10.2.2. Acute toxicity hazard classification criteria for substancesSchedule 4 of the Hazardous Substances Classification Regulations 2001 identifies five classificationcategories for substances that are acutely toxic (subclass 6.1). These categories are based on the GloballyHarmonised System for Classification and Labelling of Chemicals (GHS) (United Nations, 2007) acutetoxicity criteria (see Appendix 10C for a comparison with the GHS categories, see Appendix 10D for acomparison of the HSNO acute toxicity categories with the equivalent EU risk phrases).Category 6.1Aa. A substance for which data indicate an oral median lethal dose (LD 50 ) less than or equal to 5 mg ofthe substance per kilogram of bodyweight (mg/kg bw) as a result of acute exposure of animals to thesubstance by the oral route.January 2012 EPA0109