Allen Schaeffer of Maryland’s Diesel Technology Forum recently weighed in on Oregon’s discussion on reducing the use of older — dirtier — diesel engines in the state, a point that we seem to agree is a desirable and feasible goal (State’s emissions problems overblown, guest editorial, March 20).

However, he cited data that suggests Oregon is leading its neighbors, not trailing, in the turnover to newer cleaner engines. Unfortunately, since Schaeffer hasn’t cited where this data comes from, we’re unable to judge the information for ourselves — which is troubling as it seems to counter what data we can look at from both our state regulators and the Oregon Department of Transportation.

For instance, vehicles are classified by chassis year, not engine year, to which the Environmental Protection Agency’s requirements pertain. We know that some manufacturers made 2007 chassis-year vehicles (so they would be 2007 vehicles in the data Schaeffer cites) that did not have 2007 engines, meaning they did not meet the stricter EPA clean diesel standards.

And we know that since operators feared those 2007 engines would be less fuel efficient, that Oregon saw a near doubling of the new truck inventory in 2007 to offset that, and that the percentage of “new” trucks coming into Oregon has only just begun to recover from the hit the recession took on investments in equipment. We also know that “new” in Oregon included trucks that were previously owned and operated in California, which has been a steady stream of about 460 trucks per year. One can only assume that a portion of these are no longer legal to operate in California.

In the end, it is reasonable to say that Schaeffer’s information may not contradict the fact that the state Department of Environmental Quality has calculated Oregon’s turnover rate at 4 percent, less than half the EPA assumed rate of 10 percent. Oregon may — though we have no data source to verify — have a higher percentage of clean diesel than some other states, but we’re not replacing the older engines as fast.

We also anticipate that the situation is ripe for Oregon to see an acceleration of dumping older diesel engines in the coming years. The first compliance points for California’s new on-road and nonroad fleet standards are swiftly approaching. Many of the older engines in California’s fleets will be replaced instead of retrofitted, with them being imported into neighboring states where they are still legal, such as Oregon. Our call to action was to alert Oregonians to this very real threat, not to suggest that no clean diesel engines exist in


The other area that Schaeffer seems to not fully comprehend in the Oregon picture is on understanding the risk diesel poses to public health. He focused on our state compliance with National Ambient Air Quality Standards.

However, this misses the issue of hazardous air pollutants. HAPs are pollutants that are known to cause cancer, and are regulated under a different section of the Clean Air Act. Compliance with NAAQS standards — which does not include diesel particulates, or the other 187 toxic compounds categorized as HAPs — does not mean that there is no health threat from air pollution. 

The Oregon DEQ analyzed several of these air toxics, including diesel particulate matter, as part of the Portland Air Toxics Study. PATS data showed that diesel particulate from on-road and nonroad engines account for a significant portion of the health risk from HAPs in Portland. This was even using Oregon’s diesel particulate standard that is 30 times less stringent than Washington’s acceptable source impact level and California’s Risk assessment Health Value (0.1 v. 0.003).

Using these values instead of Oregon’s ambient benchmark concentration, the Multnomah County Health Department showed that diesel particulate matter is the leading driver of cancer risk associated with air pollution in the Portland area, some areas hundreds of times the health standard.

Oregon has done little to boost the use of clean diesel technology and retrofits. Oregon DEQ does have a clean diesel program dependent on federal money that no longer exists. Meanwhile, California is, by regulation, phasing out older diesel engines, and Washington has invested millions of state dollars to retrofit older diesel buses, trucks and ships. 

Oregonians share the goals of the Diesel Technology Forum, that to realize the advancement of clean diesel technology in our state. We would hope that the Diesel Technology Forum would support us raising awareness of the fact that newer diesel engines are significantly cleaner than older engines and to push for developing the reliable funding sources to ensure more wide scale adoption of clean diesel technology and retrofits in Oregon.

Mary Peveto is president of Neighbors for Clean Air, a Portland organization with the website She can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..

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