Tacoma Aroma: Unraveling The Mystery Of The Smell's Source

The Tacoma Aroma, also known as the Aroma of Tacoma, is an unpleasant, putrid odour associated with Tacoma, Washington, in the United States. The smell, likened to that of rotten eggs, is noticeable to motorists travelling along Interstate 5. The odour is likely caused by a combination of factors, including industrial development, natural decay, and assorted fumes. While the smell has lessened in recent years, it has not been eliminated and has contributed to a negative reputation and long-term depression of housing prices in Tacoma.

Sediment in Commencement Bay

The "Aroma of Tacoma" or "Tacoma Aroma" is a putrid, unpleasant odour associated with Tacoma, Washington, in the United States. The smell, likened to that of rotten eggs, is noticeable in certain parts of the city, particularly the Tacoma Tideflats, and by motorists travelling on Interstate 5.

The city's reputation for its stench dates back to the 1940s, though the word "aroma" in association with Tacoma dates back to 1901. The odour is likely caused by a combination of factors, including industrial development and natural sources. One of these natural sources is the sediment in Commencement Bay, the primary bay around which Tacoma is built.

Commencement Bay's sediment contributes to the Tacoma Aroma through the release of natural gases, particularly hydrogen sulfide, which combines with industrial vapours from the city's manufacturing and refining processes. The geographical layout of the region then concentrates these odours in certain areas, particularly the Tacoma Tideflats, which have been heavily industrialised in the past and present.

The sediment in Commencement Bay is a natural contributor to the Tacoma Aroma, and its effects have been exacerbated by human activity in the area. The bay's proximity to industrial sites means that the natural gases released from the sediment combine with industrial vapours, creating the putrid smell that has become synonymous with Tacoma. This combination of natural and man-made factors has resulted in a concentrated and potent odour that has persisted for decades.

While the exact contribution of the Commencement Bay sediment to the Tacoma Aroma may be difficult to quantify, it is undoubtedly one of several factors that create the unique and unpleasant odour profile. The interaction of natural and industrial sources has led to a putrid smell that, despite recent improvements, continues to be noticeable in certain areas of the city.

Sulfur from the Simpson Tacoma Kraft pulp and paper mill

The "Tacoma Aroma" is a putrid and unpleasant odor associated with Tacoma, Washington, in the United States. The smell has been described as similar to the odor of rotten eggs and is noticeable to motorists traveling along Interstate 5. The odor has been commonly known by this name since at least the early 1940s, although there are instances of the word "aroma" being associated with Tacoma dating back to 1901.

One of the attributed causes of the Tacoma Aroma is sulfur released from the Simpson Tacoma Kraft pulp and paper mill. Simpson Tacoma Kraft is a 1,200-ton/day pulp and paper mill, manufacturing bleached and natural kraft linerboard, shipping sack, specialty kraft papers, and market pulp. It is a subsidiary of the Seattle-based Simpson Investment Co.

In 1994, Simpson announced that it would expand its use of recycled fiber, which would eventually lead to the shutdown of its oldest boiler. After the recycle project was completed in 1996, the mill raised its consumption of old corrugated containers. In December 1998, Simpson permanently shut down its No. 3 recovery boiler, resulting in a significant reduction in odor-causing sulfur compounds.

By the early 2000s, the odor had been lessened but not eliminated after the Tacoma Kraft pulp and paper mill installed new combustion technologies. The reduction in sulfur compounds and the adoption of more environmentally friendly manufacturing processes have helped to improve the air quality in Tacoma. However, the aroma has not disappeared entirely, and the city has struggled with the negative reputation associated with the smell, which has even been referenced in popular culture.

A rendering plant

The "Aroma of Tacoma", also known as the Tacoma Aroma, is a putrid and unpleasant odour associated with Tacoma, Washington, United States. The smell has been described as similar to rotten eggs and is noticeable to motorists travelling on Interstate 5.

The Aroma of Tacoma is believed to be caused by a combination of factors, including industrial activities and natural sources. One of the suspected sources is a rendering plant located on the Tacoma Tideflats. Residents of Tacoma have pointed to this rendering plant as the source of the inescapable odour, which some say resembles the smell of dog food.

Rendering plants are facilities that process animal by-products and waste materials to create useful products such as animal feed, fertilizers, and raw materials for cosmetics and pharmaceuticals. The process involves cooking and breaking down animal tissues, bones, and fats, which can release unpleasant odours. While rendering plants play an important role in the circular economy by reducing waste and creating valuable resources, they can also be a source of air pollution if not properly managed.

In the case of Tacoma, the rendering plant is likely to contribute to the overall aroma of the city, particularly when there are equipment failures or maintenance issues. For example, in 2019, the Darling International Facility in Tacoma experienced an equipment failure that caused a noticeable smell throughout the city. While such incidents are not regular occurrences, they can have a significant impact on the air quality and the overall aroma of the surrounding area.

It is important to note that the Tacoma Aroma is likely a result of multiple factors, including other industrial activities and natural sources, in addition to the rendering plant. However, the rendering plant, with its unique odour of animal rendering, is a significant contributor that has drawn the attention of residents and passers-by alike.

U.S. Oil refinery

The U.S. Oil refinery in Tacoma, Washington, is one of several industrial sources that have been attributed to the city's notorious and long-standing "Aroma of Tacoma". The refinery has been specifically identified as a contributor to the noxious odour, which has been likened to the smell of rotten eggs and has earned Tacoma an unfortunate reputation.

The Aroma of Tacoma has been a feature of the city since at least the 1940s, and while it has lessened in recent years, it has not been eliminated. The odour is not pervasive throughout Tacoma but is concentrated in the Tacoma Tideflats, an area with a history of heavy industrial activity. Motorists travelling on Interstate 5, particularly those who frequently drive in the region, are often assailed by the smell.

The U.S. Oil refinery is one of several industrial facilities in the area that have been implicated in the Tacoma Aroma. The Simpson Tacoma Kraft pulp and paper mill, for instance, has been a significant source of sulphur emissions, with the Environmental Protection Agency (EPA) attributing the smell to total reduced sulphur emitted by the downtown paper mill. In addition to the pulp and paper mill, a rendering plant, and the sediment in Commencement Bay have also been identified as contributors to the odour.

The combination of these factors, along with other industrial activities in the area, has resulted in the unique and unpleasant aroma of Tacoma. The smell has had tangible impacts on the city, including contributing to a long-term depression of housing prices, as noted by research in 2003. It has also been a source of jokes and negative attention for Tacoma, with references to the odour even appearing in popular culture.

While the U.S. Oil refinery is just one piece of the puzzle, it has undoubtedly played a role in the Tacoma Aroma. The interplay of geographical factors and multiple industrial sources has created a challenging situation for the city, and efforts to improve air quality and reduce the odour have been ongoing.

Municipal sewage

In 1997, municipal officials unsealed a sewage tank that had been closed for 15 years, during a period of high humidity. This action exacerbated the odour for several weeks. The sewage tank incident is a notable example of how municipal sewage can directly impact the Tacoma Aroma.

The odour is primarily noticeable in the Tacoma Tideflats, an area with a history of heavy industrialisation. Various factors contribute to the Tacoma Aroma, including the natural decay of sediment in Commencement Bay, emissions from pulp and paper mills, rendering plants, refineries, and other industrial sources.

The Tacoma Kraft pulp and paper mill's installation of new combustion technologies in the early 2000s helped reduce, but not eliminate, the odour. Additionally, the closure of the WestRock paper mill in September 2023 may have contributed to improving air quality in the area.

While the Tacoma Aroma is not considered a significant health risk for healthy individuals, it can cause discomfort and breathing difficulties for those with asthma or lung-related illnesses. The odour has also impacted Tacoma's reputation, becoming the subject of jokes and references in popular culture.

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