Complex sentence: Safrole is regarded by the US Food and Drug Administration (FDA) to be a weak carcinogen in rats, and considered by the European Commission on Health and consumer protection to be genotoxic and carcinogenic.
Split into simpler sentences: Safrole is regarded by the US Food and Drug Administration (FDA) to be a weak carcinogen in rats. The European Commission on Health and consumer protection assumes safrole to be genotoxic and carcinogenic.