Dow ceased operations at its Sarnia site in 2009 . The plant was decommissioned , and the land have been sold to neighbouring TransAlta Energy Corporation . TransAlta produce power and steam for industry , and is the largest natural gas co @-@ generation plant in Canada . It have created the Bluewater Energy Park on the former Dow site . Lanxess produce more than 150 @,@ 000 tonnes ( 170 @,@ 000 short tons ; 150 @,@ 000 long tons ) of butyl rubber annually at its Sarnia location , and is the sole producer of regulatory @-@ approved , food @-@ grade butyl rubber , used in the manufacture of chewing gum . Within the boundaries of its Sarnia plant Lanxess have also created the Bio @-@ industrial Park Sarnia .