Though Stericycle’s North Salt Lake incineration operation has become the center of an air quality debate, the company’s latest emissions report indicates that its current rate of pollutants is far less than most industries already present in Tooele County.
According to Stericycle’s official 2013 emissions report, which was reviewed and recorded by the state, over the last year the company emitted roughly 25.4 tons of six key pollutants regularly monitored by the Utah Department of Air Quality.
If the North Salt Lake incinerator were currently located in Tooele County, that rate of emissions would make Stericycle one of the smallest industrial sources of pollution in the county, based on state data.
The department of air quality is responsible for monitoring the emissions output of nearly every industrial polluter in the state, and the division regularly publishes public emissions inventories that summarize the origin of air pollutants within each county.
These reports track the production of six key categories of pollutants — carbon monoxide, nitrogen oxides, large and small particulate matter, sulfur dioxide, and volatile organic compounds. Each one is of interest to the state because of its prevalence, and its potential harm to human life and the environment.
Pollutants of interest in Tooele County include PM 2.5, a category of small, diverse particles that are known to irritate the respiratory system. The EPA considers portions of Tooele County to be in violation of federal regulations related to PM 2.5 concentrations, because the county is believed to contribute to the amount of PM 2.5 present in Salt Lake Valley.
Volatile organic compounds, a category of organic chemicals such as formaldehyde, are also closely monitored because of the role the chemicals play in the formation of PM 2.5 in Utah.
Stericycle officials have repeatedly indicated at recent town hall meetings in the county that the company’s proposed incinerator at Rowley would produce significantly fewer emissions than the current North Salt Lake operation because of newly-adopted EPA regulations that require more effective pollution controls.
“Stericycle is considered a minor source of pollutants according to state evaluations,” said Jennifer Koenig, Stericycle’s vice president of corporate communications, in an email. “However, the emissions will be even less if the facility is moved to a new location.”
She added, “Regulations from the EPA Clean Air Act that went into effect in 2009 require that any newly constructed medical waste incinerator meet even stricter emission standards. These standards require reductions in emissions over 90 percent for several pollutants.”
However, even if the proposed incinerator’s emissions were the same as those of the company’s current facility, the company could count itself among Tooele County’s cleanest industrial citizens, based on state data.
Stericycle’s 25.4 tons of emissions included .58 tons of PM 2.5 and .18 tons of volatile organic compounds, but was mostly comprised of nitrogen oxides, a group of chemicals that in high concentrations contribute to the formation of acid rain.
On the other hand, the county’s top industrial polluters, such as Morton Salt, Cargill Incorporated, and Clean Harbors produce annual on-site emissions in the range of 115 to 540 tons, according to the most recent publicly available data from the department of air quality.
The county’s largest industrial polluter, U.S. Magnesium’s Rowley Plant, produced 3,700 tons of key pollutants in 2011, according to the department of air quality. U.S. Magnesium alone accounted for 68 percent of all emissions released by industrial sources in Tooele County.
However, industrial sources represent just a fraction — about 7 percent — of Tooele County’s total emissions, according to public records from the department of air quality.
Homes and businesses account for about 4 percent of local emissions, and vehicle traffic accounts for roughly 20 percent. But the largest source of pollution in Tooele County, which accounted for 58 percent of the area’s total emissions, was actually biological sources such as animals and plants.
Biological sources make a significant contribution to the county’s emissions because volatile organic compounds —which includes a spectrum of chemicals ranging from known toxins such as formaldehyde and benzene, to more ubiquitous compounds such as hormones and spores — comprise slightly more than half of the total pollutants released in the county, according to the department of air quality’s calculations.
Though human activities, such as painting and printing, do release volatile organic compounds, natural sources, especially plants, are considered by scientists to be the most common producers of these chemicals.
The inclusion of biological sources in emissions totals is a relatively new train of scientific thought; the EPA has revised its own calculation on the impacts of biological emissions as recently as 2002.
According to the American Chemical Society, the role of biological emissions in human health is still not entirely understood. However, the division of air quality has recognized volatile organic compounds as a key component in the formation of PM 2.5.
If biological sources — some of which may be native to the area, while others are introduced by human activity — are removed from the equation, then vehicle emissions would represent 48 percent of the county’s emissions, followed by industrial sources, non-road mobile sources, wildfires, and homes and businesses at 16 percent, 14 percent, 12 percent, and 10 percent, respectively.