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Category name:
C4, low 1,3-butadiene (<0.1%) LOA

Justifications and discussions

Category definition:
C4, low 1,3-butadiene (<0.1%)
Category description:
This is UVCB category so an order is not appropriate.
Category rationale:
The ‘C4, low 1,3-butadiene (<0.1%)’ category covers hydrocarbon streams containing high purity hydrocarbons, hydrocarbon substances with impurities and complex hydrocarbon reaction products. These hydrocarbon streams have a carbon number distribution that is predominantly C4 with a range from C3-C5 and less than 0.1% 1,3-butadiene. Category members are typically produced from the steam-cracking of naphtha and following the extraction of 1,3-butadiene from a C4-rich stream. 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 very volatile low boiling liquids, liquefied gases or gases with inhalation representing the primary route of exposure. There are no significant drivers for health effects as the major substances - butenes are simple asphyxiant and long-term irreversible effects are not anticipated. 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.

As the 1,3-butadiene content of the streams is less than 0.1% w/w (or v/v for gases) for all category members they will not be impacted by any classification or hazard assessment based on butadiene as a constituent.

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