Health Highlights: March 5, 2012

The findings of the two NCI studies are now undergoing a detailed peer and scientific review of the methodology and the conclusions, which have been the subject of great question and controversy over the last decade.

The researchers based assumptions regarding exposure on previous studies with apparent errors in the accuracy and appropriateness of some of the test measures. There are serious concerns about fundamental aspects of study design and the conclusions of the study.

The NCI studies further fail to note the tremendous changes that have taken place in diesel engines and equipment over time. Diesel engines and equipment that were the basis of these studies are in some cases over 50 years old. Like any other technology, diesel engines have changed dramatically over the course of the last half-century based on advancements in engineering and emissions control technology and new fuels.

Over the last 10 years, emissions from heavy-duty diesel trucks and buses have been reduced by 99 percent for nitrogen oxides (NOx) - an ozone precursor - and 98 percent for particulate emissions.

In addition, the new ultra-low sulfur diesel fuel that has been required since 2010 has reduced sulfur emissions by 97 percent – from 500 PM to 15 PM.

None of these advancements are considered in the two studies. Instead, the studies focus on older engines that haven’t been manufactured for decades.

Steve Hansen of MD 4:54PM March 13, 2012