Registration Dossier

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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

1,1,1,3,5,5,5 -Heptamethyltrisiloxane (H-L3) hydrolyses to trimethylsilanol and methylsilanetriol with a hydrolysis half-life of greater than 48 hours. Therefore, the environmental hazard assessment is based on the properties of the parent substance in accordance with REACH guidance for Chemical Safety Assessment.


Trimethylsilanol and methylsilanetriol are

the final products of hydrolysis reactions under the normal range of conditions of pH and temperature. However, other biotic or abiotic reactions may proceed over longer time-scales in the environment.