User Guide to Thresholds and Classification - Environmental ...

141User Guide for Thresholds and Classificationsd. See the relevant part of section 10.2.2.Criteria for category 6.1E are intended to enable the identification of substances that are of relatively low acutetoxicity hazard but that under certain circumstances may present a danger to vulnerable populations. Thesesubstances are anticipated to have an oral or dermal LD 50 in the range of 2,000–5,000 mg/kg bw and equivalentdoses for inhalation exposure. Recognising the need to protect animal welfare, testing in animals in category 5ranges is discouraged and should be considered only when there is a strong likelihood that results of such a testwould directly relevant to protecting human health.e. The acute oral toxicity classification may not be appropriate if the substance (single component or mixture) ishighly volatile or is a gas.f. The acute dermal toxicity classification may not be appropriate if the substance (single component or mixture)has a pH ≤ 2 or ≥ 11.5, or if the substance is highly volatile or a gas.g. The acute inhalation toxicity classification should be considered if the substance (single component or mixture)meets the following criteria. Substances that do not meet these criteria are not considered to be of toxicologicalconcern via the inhalation route and no classification should be considered.Single component – A classification for acute inhalation toxicity should be considered where the singlecomponent:is a gas or liquified gas;is to be used as a fumigant;is to be included in a smoke generating, aerosol or vapour releasing preparation;is to be used with fogging equipment;has a vapour pressure >1 x 10-2 Pa and is to be included in preparations to be used in enclosed spacessuch as warehouse or glasshouses;is to be included in preparations which are powders containing a significant proportion of particles ofdiameter 1% on a weight basis); oris to be included in preparations to be applied in a manner which generates a significant proportion ofparticles or droplets of diameter 1% on a weight basis).Mixtures – A classification for acute inhalation toxicity should be considered where the mixture:is used with fogging equipment;is an aerosol;is a powder containing a significant proportion of particles of diameter1% on a weight basis);is to be applied from aircraft in cases where inhalation exposure is relevant;is to be applied in a manner which generates a significant proportion of particles or droplets of diameter 1% on a weight basis);orcontains a volatile component >10%.Selecting the most appropriate LD 50 valueWhen experimental data for acute toxicity are available in several animal species, scientific judgementshould be used when selecting the most appropriate LD 50 value from among valid, well-performed tests.Consideration should therefore be given to the following.ReliabilityDoes the selected value meet the definition of ‗reliable information‘?What was the date of reference that supports the acute toxicity value? Studies conducted before theadvent of GLP and internationally accepted test guidelines may not be of acceptable quality.Are the acute toxicity values cited from an adequate source that has been peer reviewed?January 2012 EPA0109