The Inco Superstack in Sudbury, Ontario, with a height of 380 m (1,247 ft), is the tallest chimney in Canada and the Western hemisphere, and the second tallest freestanding chimney in the world after the GRES-2 Power Station in Kazakhstan. It is also the second tallest freestanding structure of any type in Canada, ranking behind the CN Tower but ahead of First Canadian Place.
It was constructed by Inco Limited in 1972 at an estimated cost of 25 million dollars; from the date of its completion until the GRES-2 chimney was constructed in 1987, it was the world's tallest smokestack. Between the years 1972-75 it was the tallest freestanding structure in Canada.
The Superstack sits atop the largest nickel smelting operation in the world at Inco's Copper Cliff processing facility in the city of Greater Sudbury.
The structure was built to disperse sulphur gases and other byproducts of the smelting process away from the city itself. As a result, these gases can be detected in the atmosphere around Greater Sudbury in a 150 mile radius of the Inco plant. Prior to the construction of the Superstack, the waste gases caused severe ecological damage in the area around Sudbury. This included an almost total loss of native vegetation in some areas, giving the city a reputation as a barren, rocky wasteland.
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