A smoke stack is a tall
exhaust chimney or pipe usually found on
refinery sites or
chemical processing plants and used for the purposes of
industrial emmissions.
The world's tallest smoke stack can be found in Sudbury, Ontario, Canada (where it is also known as the Super Stack) servicing INCO's nickel refinery in nearby Copper Cliff. The stack was, at one point, one of the world's largest point sources of sulfer-dioxide. Today, water vapor is the Super Stack's primary output as scrubbers have significantly cleaned up its emmissions.