User Guide to Thresholds and Classification - Environmental ...

219User Guide for Thresholds and ClassificationsAppendix 14C: Comparison of European Union acute toxicityrisk phrases with HSNO Act mutagenicity classificationsThe European Union (EC, 1967) risk phrases are converted into the equivalent Hazardous Substances andNew Organisms Act 1996 (HSNO Act) classification in Table 14C.1. Note that some cut-off values are nottotally aligned with HSNO Act classification categories. This is noted in the table, and for classificationpurposes a precautionary approach is advocated such that the higher hazard category is assigned.Table 14C.1: Comparison of European Union acute toxicity risk phrases with HSNO Act mutagenicityclassificationsEuropean Union risk phrasesMutagenic substancesSubstances are determined to be hazardous due to mutagenic effects if they fall into one of thefollowing categories:Category 1: Substances known to be mutagenic to humans.Category 2: Substances that should be regarded as if they are mutagenic to humans.Category 3: Substances that cause concern for humans because of possible mutageniceffects, but in respect of which available information does not satisfactorily demonstrateheritable genetic damage.Category 1Substances are determined to be hazardous and classified as Toxic (T) and assigned riskphrase R46 in accordance with the criteria given below.R46 may cause heritable genetic damageHSNO ActequivalentcategoryA substance is included in category 1, if sufficient evidence establishes a causal relationshipbetween human exposure to a substance and heritable genetic damage.6.6ATo place a substance in category 1, positive evidence from human mutation epidemiologystudies is needed. Examples of such substances are not known. It is recognised that it isextremely difficult to obtain reliable information from studies on the incidence of mutations inhuman populations, or on possible increases in their frequencies.Category 2Substances are determined to be hazardous and classified as Toxic (T) and assigned riskphrase R46 in accordance with the criteria given below.R46 may cause heritable genetic damageA substance is included in category 2 if there is sufficient evidence to provide a strongpresumption that human exposure to the substance may result in the development of heritablegenetic damage, generally on the basis of appropriate animal studies and other relevantinformation.Category 3Substances are determined to be hazardous and classified as Harmful (Xn) and assigned riskphrase R68 in accordance with the criteria given below.6.6A6.6BJanuary 2012 EPA0109