Despite all the fuss about Stericycle’s proposed relocation from a North Salt Lake neighborhood to Tooele County, it’s not always clear exactly what this company does or how it operates.
Stericycle, Inc., is the Illinois-based international company that owns and operates the North Salt Lake medical waste incinerator that has become embroiled in the ongoing Utah air quality controversy. The company has proposed to move to the Rowley area not far from US Magnesium.
Last May, the state department of air quality posted a notice that the incinerator had violated one of its permits by exceeding the company’s allotted emissions.
Come fall and the routine return of Utah’s inversions, air quality activists began pressuring the company to relocate or close the North Salt Lake operation.
Since the incinerator’s construction 25 years ago, a residential neighborhood has sprung up around the plant — a development that further adds to the debate regarding whether the company’s current level of emissions is acceptable, and whether the company abides by federal- and state-mandated regulations.
Stericycle holds that the emissions violation was the result of several unrelated equipment failures that resulted in the release of unfiltered emissions from inside the incinerator — otherwise known as a bypass event. Company officials said that they reported the incidents voluntarily, and that it was Stericycle’s first emissions-related violation in 25 years.
However, the company’s opponents hold that unreported bypass events occur frequently, causing elevated and potentially dangerous levels of pollutants to fill the surrounding neighborhood.
This much is generally well understood. But to understand exactly what all of it means, it can be useful to know the details of how and why Stericycle does business.
Stericycle officials Selin Hoboy, vice-president of legislative and regulatory affairs, and Jennifer Koenig, vice-president of corporate communications, explained this process a second time to Transcript-Bulletin staff during a tour Tuesday of their North Salt Lake facility.
Hoboy and Koenig said Stericycle deals specifically in regulated medical waste. Although the red canisters in which doctors deposit this kind of waste are often tagged with a “biohazardous” label, medical waste is not considered hazardous waste in the same sense as the environmental contaminants that are processed by hazardous waste companies in Tooele County’s west desert.
Rather, biohazardous medical waste must be handled and disposed of with care because it may contain pathogens that could infect anyone who might come into contact with it — thereby facilitating the spread of serious, life-threatening diseases.
Hoboy said some biohazardous waste, such as used needles, bandages, bloodied gloves and plastic tubing, is generally sterilized via a high-pressure, high-temperature steam process known as autoclaving.
However, autoclaving does not effectively sterilize all forms of medical waste. A small fraction of medical waste, a portion that includes trace chemotherapy and pathological waste — that is, any body part or piece of flesh that is removed and discarded during a medical procedure — requires incineration, she added. Generally, government regulations determine which waste streams go where.
Hoboy and Koenig pointed out that the company does have facilities for both autoclaving and incineration. However, the North Salt Lake plant facilitates incineration exclusively.
During the tour, which included seeing the incinerator and related equipment, the Stericycle officials further explained how appropriately sorted waste is loaded into a two-chamber incinerator and burned until the waste is reduced to ash. The remaining ash is shipped to a landfill in Tooele County for final disposal.
The smoke and fumes from this process rise into the incinerator’s second chamber, where large particles and other harmful pollutants are further degraded by intense heat.
Under normal circumstances, a large fan then pulls these fumes out of the incinerator and through the plant’s scrubbers for further filtration. But if the plant’s fan fails — which may happen during an electrical failure, or when something mechanical breaks — harmful fumes can back up in the incinerator. To prevent a possible explosion, a bypass valve is opened that vents the unfiltered emissions outside the plant.
Hoboy said the bypass valve is opened on a regular basis, two to three times a month, to allow the incinerator to shut down and cool completely for maintenance. However, because the incinerator is emptied prior to the maintenance cycle, this results in fewer emissions than a real bypass event.
Emissions from these maintenance cycles are not excluded from the company’s regular emissions allotments. Nonetheless, Stericycle is required to notify local officials whenever the bypass valve is opened, regardless of whether the bypass was scheduled or not.
Most of the time, however, emissions from the incinerator are passed through a series of three large chambers in a room adjacent to the incinerator itself. The first two chambers contain large rotors that churn the air through activated carbon and baking soda, which absorb harmful chemicals and heavy metals such as mercury and lead.
The third and final chamber contains a dry electrostatic scrubber. Particles still suspended in the air cling to the charged filter in this chamber, which funnels the collected particles, called fly ash, into large white sacks.
Fly ash contains heavy metals that are harmful to the environment and to human health, so it is officially classified as a hazardous waste. Stericycle’s North Salt Lake incinerator, which processes 15 million pounds of regulated medical waste very year, can fill a truckload of 1,000-pound sacks of fly ash in less than a month.
Hoboy said Stericycle currently sends its fly ash to Clean Harbors Grassy Mountain hazardous waste landfill in Tooele County’s west desert for proper handling and disposal.