File:20150706 - 32 - Sudbury, Ont. - Inco Superstack from Big Nickel.jpg

English: A view of the Inco Superstack in Sudbury, Ontario, Canada, as seen from the observation platform at the Big Nickel. Built in 1970 and rising to a height of 1,250 feet, this is the tallest freestanding smokestack in the Western Hemisphere, second-tallest in the world (after the one at the Ekibastuz GRES-2 power station in Kazakhstan), and second-tallest freestanding structure of any type in Canada (after the CN Tower in Toronto); part of the company's nickel smelting facility at Copper Cliff, the largest in the world. Nickel smelting has made up the backbone of Sudbury's economy for most of its history, but that came at great cost to the region's ecology, with sulfur dioxide, nitrogen dioxide, and heavy metals falling as acid rain and indiscriminately killing off the area's thick forests and the marine life in the local lakes. An imperfect solution to be sure, the Superstack was tall enough to disperse pollutants into the prevailing winds which normally blow away from the city, reducing their local effects (Sudbury's air is now considered among the cleanest of any urban center in Canada, and the environmental remediation program that sprang from the stack's construction earned the city an award from the United Nations in 1992) at the cost of greatly expanding the area affected by the pollutants (measurable levels of which can be detected in the atmosphere as far as 150 miles away). A few months before this photograph was taken, Inco announced plans to explore the option of decommissioning and demolishing the stack as part of a $1 billion Clean Atmospheric Emissions Reduction Project which they said would reduce emissions by as much as 85%, thus obviating the need for such a structure. The stack was indeed taken out of service in 2020, replaced by two smaller and more energy-efficient chimneys, but today remains standing and disused.