A Planet air pollution analysis reveals cancer risks in Whatcom County.

Story by Nick Jenner | Photos by Edward Clem

Cars drive along Interstate 5 in Bellingham, Washington

Nancy shucks sunflowers into a plastic tub. The tub rests against a tall concrete wall, separating the York Community Farm from Interstate 5. For the most part, the highway on the other side of the wall doesn’t bother Nancy. The odor and noise are annoying at times, and she and the other farm workers make sure to rinse the produce before eating it. Nancy, who declined to give her last name, works as a garden intern in one of the neighborhoods with the most toxic air in Whatcom County. A vast majority of comes from one source: diesel.

Workers tend to crops at a community garden adjacent to Interstate 5 in Bellingham, Washington

Whatcom County generally has low levels of air pollution, according to an independent analysis of Environmental Protection Agency data conducted by The Planet. However, the census blocks housing downtown Bellingham, Washington, and Western Washington University ranked highest in cancer risk from air pollution. Out of 1 million people, the air pollution levels in that neighborhood would likely cause an additional 50 people to get cancer.

But that calculation excludes diesel emissions. Add the data into a cancer-risk formula for diesel from the state of California, and the risk in those same neighborhoods skyrockets to over 1000 per million. The cancer risk for diesel alone is about 10 times that of all the other toxic chemicals combined.

This number is lower than larger cities like Seattle. According to The Planet’s analysis, the average diesel risk in Bellingham is 65 percent lower than in Seattle.

It’s difficult to pin down diesel sources. The higher levels of diesel in Bellingham could stem from the heavy-duty trucks coming to and from the Port of Bellingham, nearby buildings with diesel-emitting machinery, railroad locomotives and construction sites in the area, according to Washington State Department of Ecology’s list of diesel sources. It could also come from heavy-duty vehicles on the interstate, roaring barely a foot away from Nancy and her sunflowers.

In 2005, heavy on-road sources, like semi trucks or buses, produced over 1,450 metric tons of diesel fine particles statewide, making it the number one source of diesel emissions in the state, according to Ecology.

Kathy Strange, a technical analysis manager at the Puget Sound Clean Air Agency, said much of the air pollution in Seattle comes from a combination of on-road sources, like large vehicles, and off-road sources, including trains and ships carrying cargo to and from the port. Diesel particulate matter takes several hundred meters to dissipate, exposing many communities and employees who are near emission sources.

Sanitary Service Company trucks sit behind a fence at their depot in Bellingham, Washington. Fleet vehicles are a major source of diesel particulate matter in Whatcom County

Ecology lists diesel as the most toxic air pollutant in the state in terms of carcinogenic potency. It published multiple studies associating diesel with lung cancer, asthma, reproductive problems and cardiovascular disease. It’s not the only organization to recognize its danger.

Diesel exhaust represents around 80 percent of the cancer risk in the Puget Sound region, said Kimberley Cline of the Puget Sound Clean Air Agency. Cline works as the coordinator of a program called the Clean Cities Coalition, which aims to promote national security and environmental protection through technology to wean the country off imported petroleum.

The coalition formed in 1993 and has implemented strategies to reduce air pollution such as diesel particulate matter. The coalition runs the ScRAPS program, which encourages drivers to scrap their heavy-duty diesel trucks with older engines, and offers to sell them a discounted replacement truck with an engine from 2010 or newer.

Although agencies like Ecology, Puget Sound Clean Air Agency and even the World Health Organization see enough proof linking diesel emissions to cancer, others are more hesitant.

Exhaust pours from a tailpipe in Bellingham, Washington. Inhalation of diesel fuel poses significant risks of cancer to humans, according to the California Office of Environmental Health Hazard Assessment.

The EPA, the International Agency for Research on Cancer, the National Toxicology Program and the National Institute for Occupational Health only list diesel as a potential, likely or reasonably anticipated carcinogen.

The EPA National Air Toxics Assessment displays a map of air pollution, but doesn’t account for diesel in the cancer risk. State and federal agencies use the map to model air pollution and set priorities on certain pollutants and emitters. But without diesel, agencies could overlook polluted areas. The EPA stated the information included in its assessment is not definitive, and is merely used to narrow down areas of interest.

The air quality in Washington appears to be relatively good, if diesel is excluded from the assessment.

“Looking at our data from the last five or ten years or so, our air quality would have to be categorized as ‘overwhelmingly good,’” said Axel Franzmann, atmospheric measurement manager for Northwest Clean Air Agency, which monitors air quality in Whatcom, Skagit and Island counties.

Now, researchers in Boston and Seattle are trying to get to the bottom of just how diesel affects human health, said Sverre Vedal, a professor of environmental and occupational health sciences at the University of Washington.

That work includes monitoring people who spend several hours breathing air inside a controlled diesel emissions room. The room is designed to isolate diesel emissions from other factors in the environment. So far, the researchers have been able to link diesel-emission exposure to narrowing blood vessels, which can raise blood pressure for hours after the subjects leave the room, Vedal said.

For many people, diesel emissions are an aspect of daily life. You might create it on your way to the store, or see it rising in thick, dark plumes in the distance. You might smell it from time to time creeping over a tall, concrete wall, like Nancy.