Acute toxicity classification

Kazarians, Boykin, and Kaplan investigated tlie risk of transporting an acutely toxic and flanunable chemical 400 miles in a specially equipped railroad tank car. During its journey, the tank car clianges trains in three major rail yards. Each change of trains is teclmically described as a classification . The chemical is generally shipped one tank at a time. There are approximately 150 shipments a year. 

British Toxicology Society (1984). A new approach to the classification of substances and preparations on the basis of their acute toxicity. A report by the British Toxicology Society Working Party on Toxicology. Human Toxicol. 3 85-92. 

To obtain information necessary for the classification and labeling of the substance for acute toxicity... 

A Guidance Document on Acute Inhalation Toxicity Testing is being developed and presently exists as a draft (OECD 2004b). The document recommends the Acute Toxic Class (ATC) Method with a group size of three animals per sex, if the objective of the test is solely related to hazard classification. Limits for particle-size distribution of aerosolized test substances are suggested. The preferred mode of exposure is the nose-only, head-only, or head/nose-only exposure technique, because this mode of exposure minimizes exposure or uptake by noninhalation routes. 

OECD has published a document on a Harmonised integrated classification system for human health and environmental hazards of chemical substances and mixtures (OECD 2001b). Chapter 2.1 addresses a harmonized system for the classification of chemicals which cause acute toxicity, and Chapter 2.8 addresses the chemicals which cause specific target organ oriented systemic toxicity following a single exposure. 

Animal acute toxicity data have traditionally been used almost exclusively for classification purposes, and the classic smdy design for acute toxicity smdies has only provided information about lethality. However, with the development of the newer designs for acute toxicity smdies, more emphasis has been put on observation of animals and description of signs and symptoms of acute... 

The principles of ecotoxicological quality classification based on the TU index are included in the 2002 recommendations of the Helsinki Commission (HELCOM). The classification applies to samples of treated effluents discharged to waters from industrial plants manufacturing chemicals,98 textiles,99 and pesticides.100 HELCOM recommends testing the acute toxicity of effluent samples using two of the four suggested indicator organisms (Table 9.6). 

In 2003, Professor Persoone et al.101 developed a classification of acute toxicity levels in natural waters and effluents discharged to these waters based on two systems ... 

Acute oral toxicity is the study of adverse effects occurring shortly after oral administration of a single chemical dose or multiple doses given to an animal within 24 hours. In the evaluation of chemical safety, determination of acute oral toxicity becomes important, since it normally forms the first study step. Acute toxicity is important in establishing dose regimen for subchronic and other studies, and may provide initial information on the mode of chemical toxic action, as well as a basis of for classification and labeling. 

In Table 5.1, the minimal data needed for important classifications are indicated with reference to the categories in the left hand column. As can be seen in the table, data sufficient for classifying according to acute toxicity and skin and eye irritation... 

DFG MAK Soluble Compounds 0.5 mg/m DOT CLASSIFICATION 6.1 Label Poison SAFETY PROFILE The chromate is a human carcinogen. The soluble barium salts, such as the chloride and sulfide, are poisonous when ingested. The insoluble sulfate used in radiography is not acutely toxic. See also BARIUM SULFATE. Few cases of industrial systemic poisoning have been reported, but one investigator describes a fatal case of poisoning attributed... 

This document describes the classification criteria and the hazard communication elements by type of hazard (e.g. acute toxicity flammability). In addition, decision logics for each hazard have been developed. Some examples of classification of chemicals in the text, as well as in Annex 8, illustrate how to apply the criteria. There is also some discussion about issues that were raised during the development of the system where additional guidance was thought to be necessary to implement the system. 

The cut-off values for classification of mixtures are normally specified by concentrations expressed as % of the component substance. In some cases, for example acute toxicity (human health), the cut-off values are expressed as acute toxicity values (ATE). The classification of a mixture is determined by additivity calculation based on acute toxicity values (see Chapter 3.1) and concentrations of component substances. Similarly acute aquatic toxicity classification may be calculated on the basis of acute aquatic toxicity values (see Chapter 4.10) and where appropriate, corrosion/irritation by adding up concentrations of individual substances (see Chapters 3.2 and 3.3). Component substances are taken into consideration for application of the formula when the concentration is equal to or greater than 1 %. Some competent authorities (CA) may use this cut-off as a basis of obligation to compile an SDS. 

The harmonized classification system for acute toxicity has been developed in such a way as to accommodate the needs of existing systems. A basic principle set by the lOMC Coordinating Group/Harmonization of Chemical Classification Systems (CG/HCCS) is that harmonization means establishing a common and coherent basis for chemical hazard classification and communication from which the appropriate elements relevant to means of transport, consumer, worker and environment protection can be selected . To that end, five categories have been included in the acute toxicity scheme. 

Vapour inhalation values are intended for use in classification of acute toxicity for all sectors. It is also recognized that the saturated vapour concentration of a chemical is used by the transport sector as an additional element in classifying chemicals for packing groups. 

Classification of mixtures for acute toxicity can be carried out for each route of exposure, but is only needed for one route of exposure as long as this route is followed (estimated or tested) for all ingredients. If the acute toxicity is determined for more than one route of exposure, the more severe hazard category will be used for classification. All available information should be considered and all relevant routes of exposure should be identified for hazard communication. 

Table 3.1.2 Conversion from experimentally obtained acute toxicity range values (or acute toxicity hazard categories) to acute toxicity point estimates for classification for the respective routes of exposure...

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