The study involved testing UK and US truckers and miners who were exposed to emissions from diesel engines produced between the 1970s and 1990s. Researchers said it was "unclear" if the results are applicable to more modern diesel engines but added that the findings were consistent with earlier studies, since this isn't the first time there has been an official link between diesel exhaust and cancer. The new Utrecht study also said that lifetime exposure to diesel exhaust causes as many as 689 extra lung cancer deaths for every 10,000 workers exposed, an additional 6.9 percent risk. Federal workplace standards state that any scenario where the death-risk rises 0.1 percent is considered notable.
The good news is that the study (read a synopsis below) says the number of "uncontrolled" older diesel engines in the US, Europe and Japan has dropped "substantially" in recent years. The problem is that as some engines get cleaner, other problems arise. Independent researchers at TUeV Nord in Germany recently found the advanced gasoline engines can emit 10 times more particulates and harmful carcinogens than today's new diesel engines. The new GDI engines are even worse than earlier gas engines, spewing up to 1,000 times the harmful emissions because of the higher-pressure cylinders. Given the strict emissions regulations in Europe and around the world, we expect GDI engines will soon get the same kind of regulatory scrutiny that diesel mills have had up until now.
Nov 27, 2013
Vermeulen R, DT Silverman, E Garshick, J Vlaanderen, L Portengen, K Steenland. Exposure-response estimates for diesel engine exhaust and lung cancer mortality based on data from three occupational cohorts. Environmental Health Perspectives. 2013. http://1.usa.gov/1gcpfX9.
Synopsis by Brian Bienkowski
The World Health Organization concluded last year that diesel exhaust is carcinogenic.
An estimated 6 percent of lung cancer deaths in the United States and the United Kingdom – 11,000 deaths per year – may be due to diesel exhaust, according to a new study.
Emission standards for diesel engines have become more stringent in recent years, but their exhaust still plays a significant role in lung cancer deaths among truckers, miners and railroad workers, the authors wrote. In addition, diesel exhaust still poses a major cancer threat for people living in dense cities or near highways, they said.
Truckers and miners exposed over their careers to diesel exhaust face a risk of deadly lung cancer that is almost 70 times higher than the risk considered acceptable under U.S. occupational standards. The scientists calculated the lifetime risk for these workers at up to 689 extra lung cancer deaths per 10,000 workers exposed. In comparison, one cancer death per 1,000 workers is used to set federal workplace standards.
In addition, people in urban areas face a lifetime risk of lung cancer that is 10 times higher than the acceptable risk used in U.S. health standards, according to the study. An estimated 21 per 10,000 people exposed to the amount of diesel exhaust commonly found near U.S. highways would be at risk of dying of lung cancer over their lifetime. That compares to the risk of one death per 100,000 people that is used to set air-quality standards.
To come up with their calculations, the researchers from Emory University and several other U.S. and European institutions used data from three previous studies of workers – two of truckers and one of non-metal miners – as well as national death statistics for the United States and United Kingdom.
They estimated that 4.8 percent of lung cancer deaths in the United States and the United Kingdom is due to occupational exposure to diesel exhaust, while 1.3 percent is due to environmental exposures to the exhaust. [Editor's Note, 11/27/2013: Corrected error in description of percentages.]
"With millions of workers currently exposed to such levels, and likely higher levels in the past, the impact on the current and future lung cancer burden could be substantial," the authors wrote.
The researchers said their estimates "are far from precise and depend on broad assumptions." But they said their findings are "generally consistent" with past findings. Other factors, such as smoking, were not taken into account. They used the assumption that smoking does not modify effects of diesel exhaust.
The World Health Organization concluded last year, after reviewing health data for workers, that diesel exhaust is carcinogenic.
Diesel emissions have declined substantially over the past few years in the United States and Europe since new engine standards were initiated. More than 50,000 high-polluting diesel engines were cleaned up or removed from U.S. roads between 2008 and 2010, according to an Environmental Protection Agency report. About 230,000 tons of soot and smog-causing pollutants were eliminated, according to the report.
However, while buses and trucks have largely adopted cleaner technology, it's taken longer for off-road engines, such as farm and construction vehicles.