Engine manufacturers challenge California report on diesel exhaust

23 April 1998

The Engine Manufacturers Association issued the following statement challenging the recent California report on the toxicity of diesel exhaust:

Obsolete data and improperly applied research continue to invalidate a California report linking diesel exhaust with lung cancer. These key issues were among the reasons cited by the Engine Manufacturers Association (EMA) in voicing its continued opposition to the findings of a scientific review panel released yesterday in South San Francisco.

The findings, issued in the report “Proposed Identification of Diesel Exhaust as a Toxic Air Contaminant”, were commissioned last year by the California Environmental Protection Agency’s Air Resources Board (ARB) and the Office of Environmental Health and Hazard Assessment (OEHHA).

“The diesel engine industry is angered that this report does not use and reflect the ‘best available scientific evidence’ and 'sound scientific knowledge,' as mandated by law," said Glenn Keller, executive director, EMA. "We are troubled that despite repeated conversations with the panel and the OEHHA staff, there seems to be little willingness to acknowledge deficiencies in the data and the inappropriate application of scientific research.”

EMA’s concerns with the report are twofold. First, it relies on information derived from tests that were conducted using engine and fuel technologies from the 1960s. Secondly, the report attempts to establish health risk using data from a 1988 study of railroad workers despite the author's insistence that his data is being applied improperly. Both the US EPA and the World Health Organization agree with his admonishment, and have rejected the 1988 study as inadequate for the manner in which the report uses it. “Despite this report, we will continue to support the further research efforts of academic, government and independent researchers to evaluate the potential health impact of diesel exhaust using the best scientific information.”

EMA members continue to work with the USEPA and CARB to develop emissions reduction strategies for cleaner diesel engines. Through these efforts, today's truck engines emit nearly 70% less NOx and 90% less particulates than in 1987. By the year 2004, thanks to an agreement between engine manufacturers, CARB and federal EPA, diesel truck NOx emissions will also be reduced an additional 50% from current levels.

Source: EMA | Contact: Charlie Souhrada, 312.527.6680