The Suncor Energy oil refinery in Commerce City released high levels of sulfur dioxide Wednesday morning after a malfunction, and those excess emissions could have caused area residents to experience asthma attacks and have problems breathing while exercising or working outdoors.

The Colorado Department of Public Health and Environment announced the spikes in sulfur dioxide Wednesday evening, saying they were higher than normal but did not violate federal air quality standards.

It is not known whether the release exceeded the amounts of emissions allowed by the refinery’s federal air permit.

The National Ambient Air Quality Standard for sulfur dioxide is 75 parts per billion per hour. Monitors operated by Cultivando, a nonprofit in Commerce City that advocates for improved air quality, detected one spike at 155 parts per billion and another at 186 parts per billion, according to a news release from the state health department.

Air monitors showed sulfur dioxide emissions had returned to normal levels by Wednesday afternoon, the agency said.

Suncor reported to the health department’s Air Pollution Control Division that two units used in making gasoline tripped offline, causing the refinery to release excess sulfur dioxide from an incinerator and to burn off acid gas through a flare, state officials said.

There also was an elevated level of hydrogen sulfide in a fuel gas system.

Sulfur dioxide is a compound that is released during the burning of fossil fuels at power plants and other industrial plants. Even short-term exposure can harm the respiratory system and cause breathing problems, according to the Environmental Protection Agency. People with asthma, particularly children, are especially sensitive to it.

Sulfur dioxide also can harm plants and trees. It also contributes to the brown haze that often blankets the Front Range.

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