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World Health Organization Recognizes Diesel Exhaust from Engines Causes Cancer

Diane Bailey

Posted June 12, 2012

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The International Agency for Research on Cancer (IARC), a branch of the World Health Organization, released its finding today that diesel engine exhaust will now be classified as “carcinogenic to humans (Group 1)”.   This recognition, coming from the world’s foremost authority on dangerous carcinogens, has been a longtime in coming since its 1988 finding that diesel exhaust is a “probable” human carcinogen (“Group 2A”) .  In addition to all the health hazards of diesel exhaust – asthma, respiratory and cardiac illness to name a few – diesel exhaust causes lung cancer, a deadly disease.  Diesel exhaust is also associated with increased risk of bladder cancer.

The state of California found diesel exhaust to be carcinogenic in 1998 based on dozens of human epidemiological studies showing long-term occupational exposure to diesel exhaust that can be associated with a 40 percent increase in the relative risk of lung cancer. These earlier findings are consistent with recent findings from several joint studies by the National Cancer Institute and the National Institute for Occupational Safety and Health showing greatly elevated risks of lung cancer among miners exposed to heavy diesel equipment.  The new miner studies undoubtedly provided the final evidence necessary for the IARC finding on diesel.  Those studies are also important because they evaluated smokers and non-smokers concluding that diesel exhaust exposure is similar to smoking.

With solid evidence of the health harms of diesel pollution, Dr. Christopher Wild, Director of IARC, notes that their finding “sends a strong signal that public health action is warranted.” He notes further that “this emphasis is needed globally.”  With millions of old, dirty diesel engines in use around the world, we need governments to commit to the phase in of cleaner diesel fuels and replacement of older engines with much cleaner modern diesel technology that is widely available. Here in the U.S. we need sustained commitment and funding for the replacement of old, polluting diesel engines.

Every year tens of thousands of people die from exposure to diesel pollution in the U.S., and many more die from diesel exhaust around the world.  These deaths and all the disease and suffering caused by diesel pollution can easily be prevented with the use of modern engine technology.  It is time to retire the old smoking habits of diesel.

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Sarah QuinnJun 15 2012 11:15 AM

So, with modern engine technology, will NRDC support highly fuel-efficient diesel cars in the US ?? Even if they have higher per gallon emission pollutants, if the mpg is twice as good, wouldn't that be better?

Diane BaileyJun 15 2012 11:48 AM

Yes, we support all fuel-efficient cars, including diesels, that can meet current health-protective emission standards.

Irvin DawidJun 15 2012 04:27 PM

Sorry, Sarah - don't get your point - or if I do, I would have to ask you - are you will to sacrifice you health for greater energy efficiency?

Question for Diane: Just skimmed the report, but I did hear about it recently on NPR's Morning Edition - the commentators stated that the IARC may have been evaluating OLDER diesel engines - and with the advent of low sulfer diesel fuel and the new engines, the diesel emissions are comparable to emissions from modern gasoline engines. The problem, they said, is that diesel engines are so durable that they are not retired and replaced witht he new engines. Did the study separate the old from the new diesel engines?

Irvin DawidJun 15 2012 05:55 PM

another question, Diane. How would you respond to the point made by the DTF spokesman?:
"....the Diesel Technology Forum, a group representing companies including Mercedes, Ford and Chrysler, said in a statement. "In southern California, more fine particles come from brake and tire wear than from diesel engines."

Diane BaileyJun 15 2012 06:42 PM

Irvin, good questions. Yes, it's true that diesel exhaust is much less of a problem from well maintained new or DPF-retrofitted engines, primarily because more than 90% of particulate and toxics are removed by the advanced filters.

And DTF is correct that fine particles from brake and tire wear are a significant problem. This is why we recommend that housing and other sensitive sites like schools always stay a minimum of 200 feet (preferably more) away from freeways and other high traffic areas. As the vehicle fleet gets cleaner over time this "fugitive" road dust will still pose a health risk directly next to busy roadways.

BSJun 15 2012 07:45 PM

Interesting to learn about the brake and tire dust. So, reducing the latter would be another benefit of hybrids and plug-ins that use braking systems that recover the energy rather than simply waste it via traditional brakes.

What could reduce the pollution from tire dust?

IrvinJun 16 2012 04:44 PM

Brake and tire particulates: BS, I'm curious to see how Diane responds, but regarding the brakes, I don't see how a hybrid would differ from a conventional vehicle. It is my understanding that the 'regenerative energy' from braking is entirely separate from the particulate matter that brakes emit.

I like your second question, BTW.

Diane BaileyJun 16 2012 05:20 PM

The best way to reduce particulates from break and tire wear is to drive less (or in jargon: Reduce VMT).

BSJun 16 2012 06:56 PM

True. We do that as best as we can. Bus to work, maybe 12k miles/yr between my wife and I. Before we moved to the big city, it was about 9k mi/yr.

Irvin--I'm not sure how hybrid regenerative brakes work, but if they are not relying on friction like traditional pads (i.e. recovering energy and converting to electricity, instead), then you would expect to have little or no dust from brake pad friction.

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