Complex sentence: Crown Zellerbach developed the DMS/DMSO manufacturing technology in use today; they also built the original DMSO plant in the 1960s at the site where Gaylord Chemical currently operates.
Split into simpler sentences: Crown Zellerbach developed the DMS/DMSO manufacturing technology in use today. They also built the original DMSO plant in the 1960s at the site where Gaylord Chemical currently operates.