LONDON (Bloomberg) -- Exhaust fumes from diesel engines cause lung cancer, a World Health Organization agency said for the first time, citing a review of studies.
Diesel exhaust was also linked to an increased risk of bladder cancer, the International Agency for Research on Cancer, based in Lyon, France, said in a statement on Tuesday.
The group published the findings after a review over eight days by a panel of scientists. An earlier review, in 1988, classified diesel engine exhaust as "probably carcinogenic."
The agency isn't providing guidelines on what level of exposure is carcinogenic, leaving it up to national and international regulatory authorities to weigh its conclusion, Christopher Wild, director of the agency, told reporters Tuesday on a conference call.
"The scientific evidence was compelling and the working group's conclusion was unanimous: Diesel engine exhaust causes lung cancer in humans," Christopher Portier, chairman of the IARC working group, said in the statement. "Given the additional health impacts from diesel particulates, exposure to this mixture of chemicals should be reduced worldwide.''
The review of older studies may not take into account advances in diesel technology over the last decade, Steve Hansen, a spokesman for the Diesel Technology Forum in Washington, said in an e-mailed statement. The group represents global diesel engine manufacturers, automakers and oil refiners. Members include Deere & Co., Ford Motor Co. and BP Plc.
Nitrogen oxide emissions from heavy-duty trucks and buses have been reduced by 99 percent and particulate emissions by 98 percent over the last 10 years, Hansen said. While the amount of particulates and chemicals are reduced with these changes, it is not yet clear how they may translate into health effects, the IARC said. ''Research into this question is needed.''
Existing vehicles without these modifications will take many years to be replaced, particularly in less-developed countries where regulatory measures aren't as stringent, the IARC said.
The group added that gasoline engine fumes are also ''possibly carcinogenic,'' reiterating its 1988 finding.
Cancer killed 7.6 million people worldwide, the leading cause of death globally in 2008, the most recent year available, the WHO said. Lung cancer was the most lethal type, accounted for 18 percent of all cancer deaths, the agency said.
The IARC had been planning since 1998 to re-evaluate the cancer-causing potential of diesel fumes. The concern was re-emphasized by the publication in March of results from a U.S. National Cancer Institute study that found exposure to diesel fumes increased risk of death from lung cancer in miners, the agency said.
By classifying cancer risks, the IARC provides scientific advice to governments. The agency lists substances as carcinogenic, probably carcinogenic, possibly carcinogenic, not classifiable and probably not carcinogenic.