In Pearson (later Smith) v. Inco, the largest collective legal action against environmental damage in the history of Canada, residents of Port Colborne, Ontario, filed a collective suit against Inco (now Vale) . Residents claimed that the refinery is responsible for heavy metal contamination of their soils, creating serious health risks and diminishing property values . The lawsuit was acknowledged as legitimate by a Canadian court of law in 2005. It is the first time that such an initiative has been accepted .
In the late 90s, the Port Colborne community detected that soil and water of the region has been “seriously contaminated with nickel and nickel oxide. This pollution puts the population's health at risk, and may cause deadly diseases, such as cancer and leukemia. The Vale Inco refinery is situated close to agricultural and residential areas. In 2001, Port Colborne's inhabitants filed a collective suit against the company” .
Residents claimed that the “refinery is responsible for the heavy metal contamination of their soils, and Inco admitted to contamination by nickel, copper, cobalt and arsenic. An estimated 20,000 tonnes of nickel oxide, a carcinogen, was spread over the Port Colborne area during the refinery's operation .” Emissions from the 500-foot smoke stack on the refinery led to a build-up of nickel particles in the soil in the surrounding area” . “In some areas of Port Colborne, nickel exceeds 20,000 parts per million (ppm). Ontario's Ministry of the Environment considers the safe upper threshold for nickel in residential soils to be 200 ppm” .
Port Colborne residents also claimed that their property values were diminished by the levels of nickel emitted from Inco's refinery  In 2001, a class action lawsuit was launched, with 8,000 plaintiffs who originally sought $750 million in damages to health, property value and quality of life . "The class of claimants included everyone who owned residential property in an area that covers most of Port Colborne, approximately 7,000 properties. They alleged that because of the public health concerns the nickel deposits provoked, their property values did not increase at the same rate as comparable values in other small cities nearby" .
Although that suit failed in 2002 to be certified, it was subsequently modified to focus on devaluation of property. The suit was certified on November 18, 2005. The plaintiffs settled out of court with all defendants except Inco. In late June 2006, Inco’s efforts to stop the class-action lawsuit were dismissed by the Supreme Court of Canada (this is the same years that Inco was taken over by Vale). The lawsuit that resulted in the July 6 verdict went to trial in October 2009 .
After more twists and turns, in 2012 the Supreme Court of Canada sided with Vale and denied the residents the awarded compensation. Court costs in the amount of CAD$1,766,000 were awarded to Vale .
1960s: Inco began buying up land in Port Colborne and became one of the main landowners. Many “believed that this was an apparent attempt to buy contamination concerns” .
1984: Inco's base metal refinery closed. Emissions from the refinery had resulted in soils contaminated with concentrations of nickel, copper and cobalt above the Ontario Ministry of the Environment's "soil remediation criteria” .
1990s: Two studies, one in 1997 and another in 1999 found "adverse health effects which may have resulted from environmental exposures. After a series of public meetings between the City, the Ministry of the Environment (MOE) and Inco, it was decided to perform a Community-Based Risk Assessment, a process designed to determine whether the contamination poses a threat to the current, past, or future residents of Port Colborne, and what Inco must do to clean up the contaminated areas .
2000: Inco’s chemical pond in Port Colborne ‘began seeping’. For decades, Inco had been dumping electrolyte nickel or "green liquor" into an aquifer below the Rodney Street neighbourhood. Over time, a fracture developed in the bedrock. By 2000, this "green liquor" was seeping into Lake Erie and surrounding areas . The Ministry of the Environment released the results of a phytotoxicology study. This report on the effects of nickel levels on plant life identified “hot spots” where the levels were very high. The Ministry eventually ordered Inco to “remediate” 25 properties with particularly high levels .
June 2000: Two residents, Smith and Edwards, requested that the Ministry of Environment test the soil on their Rodney Street area property. Their property contained between 14,000 and 16,000 ppm nickel, and over 600 ppm lead .
2001: Two Port Colborne mothers (Wiggins and Smith) founded Neighbours Helping Neighbours to tackle the nickel contamination problem in their city. Smith became the lead plaintiff in the lawsuit . Residents launched Lawsuit 
2002: The suit failed to be certified in 2002 (but it was subsequently modified to limit the class, and focus solely on devaluation of property).
October 2003: Wiggins motivated others to organize a global day of action against Inco. In October, people around the world demonstrated and held public presentations, film screenings and vigils in Newfoundland, Ontario, Guatemala, Indonesia and Kanaky-New Caledonia in the first global day of action against a Canadian mining company. November 2005: suit was certified on appeal .
September 2006: Inco Canada was taken over by Brazilian owned Vale (known at the time as “Companhia Vale do Rio Doce, or C.V.R.D.” 
October 2009: three-month trial that started .
July 2010: “Ontario Supreme Court Justice J.R. Henderson sided with the residents and awarded more than 7,000 households in Port Colborne a total of $36 million. Households in the Rodney Street area, in the shadow of the nickel refinery, were each awarded $23,000 while those living on the east side of Port Colborne were each awarded $9,000, and the west side, $2,500. Vale (formerly Inco) said the company would appeal” . Vale appealed the ruling to the Ontario Court of Appeal, who found in 2010 that the plaintiff had not provided sufficient evidence of economic harm, raising the legal burden of proof.
Oct 2011: The Ontario Court of Appeal dismissed the environmental class action and reversed the award of $36-million to Port Colborne residents. The three-member panel of the court unanimously ruled that the plaintiffs did not prove that Inco was liable to them. Even if they had succeeded on that front, the court said, the plaintiffs failed to show any actual loss to Port Colborne’s property appreciation rates. On top of throwing out the claims, the court ordered the plaintiffs to pay $100,000 in costs to Inco. 
April 2012: the Supreme Court of Canada sided with Vale and denied the residents the awarded compensation. Court costs in the amount of CAD$1,766,000 were awarded to Vale .