Complex sentence: Chlordane is a known persistent organic pollutants (POP), classified among the "dirty dozen" and banned by the 2001 Stockholm Convention on Persistent Organic Pollutants.
Split into simpler sentences: Chlordane is a known persistent organic pollutants (POP). It was classified among the "dirty dozen" and was banned by the 2001 Stockholm Convention on Persistent Organic Pollutants.