Complex sentence: Site clean up began in October 2006, and was scheduled to be finished within a year, as it had suffered chemical contamination, as it was principally used to recycle copper and other metals from old wires.
Split into simpler sentences: Site clean up began in October 2006, and was scheduled to be finished within a year. The site had suffered chemical contamination, as it was principally used to recycle copper and other metals from old wires.