The Nanticoke generating station, a sprawling, coal-fired power plant on Lake Erie, is Ontario's largest single source of air pollution particles that cause summertime haze and respiratory damage, a study to be released todaysays.
The study, by the Ontario Clean Air Alliance, says that in 2002 the station led the province in emissions of what is called particulate matter, the nearly invisible particles of soot that are considered the most damaging component of air pollution.
Also that year, the station's total output of mercury reached its highest level ever reported, and much of the dangerous heavy metal was added to a landfill at the site, according to the report.
Nanticoke, one of the world's largest coal-fuelled generating stations, is about 60 kilometres south of Hamilton.
Most of its emissions are carried on prevailing winds to the Greater Toronto Area, other parts of Southern Ontario, and adjacent parts of New York state.
"Nanticoke is a major public health threat," said Jack Gibbons, spokesman for the alliance, an organization backed by municipal, public health and environmental groups.
The new Liberal government has promised to shut the Nanticoke station in three years, even though it is the source of about 10 per cent of Ontario's electricity.
The government hasn't said how it will replace the output from the station, but Mr. Gibbons said the report bolsters the environmental and public health arguments for shuttering it.
"It shows that a coal phaseout is essential to protect public health," Mr. Gibbons said.
The provincial government owns the station through Ontario Power Generation.
The company defended its environmental record, saying the plant's emissions comply with government standards.
"Nanticoke not only meets, but betters in most cases all of the regulatory requirements that we have for the plant," said John Earl, an Ontario Power spokesman.
The report tabulated 21 contaminants emitted by the station, but not all of the compounds have output caps.
According to Mr. Gibbons, there are binding regulatory ceilings on only two of the major pollutants from the station: nitrogen oxides, which cause smog, and sulphur dioxide, which causes acid rain.
The report was based on preliminary pollution release data for 2002 that Ontario Power supplied to Environment Canada .
Federal law required the country's larger companies to report to Ottawa each year their discharges of hazardous compounds.
Environment Canada expanded its list of reportable pollutants in 2002 to require figures on emissions of particulate matter for the first time.
These pollutants, known by their initials as PM, have been linked to such adverse health effects as asthma and chronic bronchitis, and to premature death.
Recent research has found particulates to be extremely dangerous because their small size allows them to penetrate deep into lung tissue when inhaled, leading to tissue damage.
During 2002, Nanticoke discharged 7,767 tonnes of particulates, about 13 per cent of the provincial total.
Particulates are extremely small, only 2.5 microns to 10 microns in size.
A micron is one thousandth of a millimetre, and it would take a few dozen of these particles to equal the width of a human hair.
During 2002, the report said, Nanticoke's air emissions of hydrochloric acid, hydrogen fluoride and nitrogen oxides were the largest in the province.