Masotene
Trichlorfon: Insecticide and broad-spectrum wormicide. Highly toxic
Also turns into an even more toxic compound within a very short time when exposed to traces of moisture dichlorvos (DDVP). Overall, its use could only be approved in a few special cases under very precisely defined conditions. More fish have probably been killed than cured by the careless use of Masoten .
The product has since been withdrawn from the market and the licence withdrawn. The continued use of Masotene would therefore be an offence against the Medicinal Products Act and therefore liable to prosecution.