Hydrocarbons, C5-8

Categories

Category name:

Aliphatics & Cyclics C5 and higher - LOA

Justifications and discussions

Category definition:

aliphatic and cyclic C5 and higher

Category rationale:

The aliphatic and cyclic C5 and higher category covers hydrocarbon streams typically produced by the distillation of products from an aromatic process or distillation of hydrotreated naphtha. These hydrocarbon streams have a carbon number distribution that is predominantly C5-C7. All of the streams in this category a complex substances containing >20% alkyl and/or >20% cyclic hydrocarbons and between 0.1 and 15% benzene. Companies importing streams will need to confirm that such streams meet the chemical description and are in domain.

It is reasonable to assume that the phys-chem and environmental fate properties of the category members will be very similar due to the small spread of carbon numbers. The streams will have similar environmental effects as their constituents cover a narrow carbon range and all act in similar manner, via narcosis. With regard to mammalian endpoints, category members are volatile liquids with inhalation and skin contact representing the primary routes of exposure. CNS depression, skin irritation (marker substance: cyclohexane) and irreversible effects (the latter linked to the presence of n-hexane, toluene and benzene) are likely to have the greatest impact on the health hazard assessment. It can therefore be assumed that streams meeting the applicability domain will behave in a similar manner and therefore the use of read-across is valid. For mammalian endpoints, the classification of these streams will be driven by the content of benzene, which is between 0.1 and 15% for all category members. Although these streams may be classified for aspiration hazard, this is not considered to represent a relevant health effect of these streams under conditions of normal use.