A study of 31,135 trucking workers indicating they showed an elevated risk of lung cancer with increasing years of work does not accurately portray the industry, said Glen Kedzie, vice president and environmental affairs counsel of the American Trucking Associations. He was responding to a study released by the California Air Resources Board (CARB).
CARB is considering requiring that diesel exhaust filters be installed on trucks starting in 2010, with nearly all vehicles upgraded by 2014. The group also is considering incentive funding to truck owners in the amount of $1 billion in grants and loans.
Kedzie said the study focused on data from as long ago as 1985.
"Engine makers and trucking companies worked together to meet new EPA engine emission and fuel standards for 1984, 1988, 1990, 1991, 1993, 1994, 1998, 2002, 2007, and 2010 trucks, drastically reducing emissions, and few of the older trucks are still on the road," he said. "In 2002, new trucks incorporated exhaust gas recirculation (EGR) and other emission-control technologies to reduce tailpipe emissions of nitrogen oxide (NOx) by almost half."
According to CARB, the researchers limited their study to Teamsters older than 39 years with at least one year on the job, and examined men working as clerks, mechanics, long-haul drivers, dockworkers, combination workers, and in pick-up and delivery.
Work records were obtained for the men in 1985. The group conducting the survey assessed lung cancer mortality through 2000 using the National Death Index, and used an industrial hygiene review and current exposure measurements to identify jobs associated with current and historical use of diesel-, gas-, and propane-powered vehicles. They indirectly adjusted for cigarette smoking based on an industry survey, according to the National Institutes of Health (NIH) website.
Kedzie also noted that in 2007, diesel trucks incorporated diesel particulate filters to reduce tailpipe emissions of particulate matter by 90%.
"These trucks also began the first half of what will be a 90% reduction in NOx emissions," he said. "Today, on-road diesel engines contribute just 1% of the nation’s total emissions of volatile organic compounds, carbon monoxide, and sulfur dioxide and less than 1.5 % of the nation’s total emissions of fine particulate matter.
"Fine particulate emissions from on-road diesel engines have been cut by more than half over the past decade. On-road heavy-duty diesel trucks produce half as much fine particulates as off-road sources, including bulldozers, tractors, railroad locomotives, and ships.
"It is also important," said Kedzie, "to note that motor carriers voluntarily supplied driver records to these researchers in hopes of finding ways to improve conditions for their highly valued drivers."