July 10, 2000

Carol M. Browner
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460

Re: Proposed sulfur levels in diesel fuel; Proposed heavy duty diesel engine rule

Dear Ms. Browner:

The Washington Environmental Council (WEC) is a statewide coalition of 90 member groups and thousands of individuals working to protect, restore, and enhance the environment of Washington State. We thank you for this opportunity to provide the following comments relating to sulfur levels in diesel fuel.

WEC supports the newly proposed low sulfur diesel rule which would set the upper limit for sulfur in diesel fuel at 15 ppm by mid 2006. WEC also supports the newly proposed heavy duty diesel engine rule which would be fully phased in by 2010. These new rules will result in a 90 percent reduction in PM2.5 and oxides of nitrogen from heavy duty diesel.

Following is a brief description of why WEC supports the proposed rules:

Diesel exhaust is a major source of fine particulate pollution. Numerous public health studies over the last few decades have found links between fine PM and a wide variety of health impacts, including increased hospital admissions for cardiovascular disease, pneumonia, and chronic obstructive pulmonary disease (asthma and emphysema), as well as premature mortality.

Diesel exhaust contains over 40 chemicals that are listed by California and EPA as toxic air contaminants, probable human carcinogens, known human carcinogens, reproductive toxicants and/or endocrine disrupters. Many of these toxics adhere to the fine particulate surface. For this reason diesel particulate and/or whole exhaust has been classed or recommended to be classed as a probable human carcinogen be the state of California, the EPA, the National Toxicology Program Advisory Board, the National Institute of Occupational Safety and Health, the World Health Organization's International Agency for Research on Cancer (IARC), and the National Institute of Health.

Because of the potential for significant PM2.5 reductions resulting from both low sulfur fuel and diesel engine improvements, the Puget Sound Clean Air Agency (formerly Puget Sound Air Pollution Control Agency), responsible for air quality in King Pierce, Snohomish, and Kitsap Counties of Washington State, has selected both lower sulfer diesel and cleaner diesel engines as effective strategies in helping to reduce PM2.5 concentrations in areas within its jurisdiction.

Prevailing winds, especially during summer months, carry Puget Sound pollutants, including PM2.5 and ozone south east, into Mt. Rainier National Park. A reduction in sulfur content of diesel fuel, by reducing PM2.5, would improve regional visibility, and would also help to reduce the amount of sulfuric acid released into the atmosphere, which would help reduce the effects of acid rain on lakes, forests, and vegetation.


Joan Crooks
Executive Director
Washington Environmental Council