Thanks for alerting your readers to the Natural Resources Defense Council-Sierra Club campaign to convince the Washington Metropolitan Area Transit Authority to replace its toxic diesel buses with cleaner bus technology (“Bad Air Day,” 5/5). Unfortunately, the article left out some critical facts, neglected to mention the profound health threats posed by diesel exhaust, and failed to challenge inaccurate statements made by WMATA chief bus manager Jack Requa. Here are just a few major holes in the story:

1. The beginning of the article suggested that bus garages are no longer a problem for neighborhoods. Not true. There is a major controversy at the Carter Barron bus barn, for example, where residents are extremely angry about soot and noise. The area’s advisory neighborhood commission recently voted to ask Metro to close down the bus barn.

2. The article suggested that our regional air problems are largely the result of suburban cars. In fact, diesel engines are infinitely worse than conventional gas engines. They account for 66 percent of the particulate pollution and 26 percent of the nitrogen oxide pollution from vehicles. Exhaust from Metro’s 1,300 diesel buses is the equivalent of exhaust from 130,000 cars. The public sector can’t do much about the cars private citizens drive, but it can do something about the buses that run through our neighborhoods every day.

3. The term “clean diesel” is an oxymoron. It’s like saying “clean dirt.” Metro’s newer buses may be cleaner than the buses it is running that were built in the late ’60s and early ’70s, but they still emit huge quantities of smog-forming nitrogen oxide gases and particulate matter, which is associated with increased asthma emergencies, bronchitis and other cardiopulmonary ailments, cancer, heart ailments, and premature death. Diesel exhaust also includes more than 40 toxic air contaminants, such as arsenic, benzene, 1,3-butadiene, cadmium, chlorine, cyanide compounds, dioxins, inorganic lead, and toluene. A number of these are “probable” or “known” human carcinogens. According to the Health Effects Institute, diesel particulate matter elevates cancer risk by 25 percent to 30 percent, making it comparable to secondhand smoke.

The bigger issue is how diesels stack up against compressed natural gas (CNG) engines. Remarkably, the article failed to compare them. Even Requa, in a meeting with us last December, conceded that CNG offers superior emissions performance over diesel. CNG buses emit virtually no particulate matter or toxic chemicals, and 60 percent fewer nitrogen oxides than diesel buses.

4. The article said Metro uses “special low-sulfur fuel.” Not true. The agency is filling its buses with diesel fuel that has sulfur levels of 250 parts per million (ppm). Even 50 ppm is too high for advanced particulate traps or to mitigate the health problems associated with diesel exhaust. Truly low-sulfur fuel, with a sulfur content of 15 ppm, will not be widely available until at least 2006.

5. The article gave Requa a lot of space to explain that Metro cannot afford to buy CNG buses and would have to spend several million dollars to build CNG fueling facilities. That would mean fewer buses on the streets, according to Requa. He also said it is too late to do anything about Metro’s three-year 360-bus order. We’d like to correct the record.

Our Clean Bus Campaign is not asking Metro to spend any more money or alter its procurement schedule. We want Metro to buy as many buses as it needs. But, as we pointed out to Requa last December, there are at least 10 federal programs at three agencies that are helping transit agencies across the country pay for the incremental costs of CNG buses, which cost about 18 percent more than diesel buses. In any case, according to the Department of Energy, “the typical CNG bus could pay for itself in just a little more than three years” because compressed natural gas is considerably cheaper than diesel fuel.

Federal programs will also help pay for converting fueling and maintenance stations. Moreover, private companies will build fueling stations for free. Los Angeles just arranged for a company to build two. One will take six months to build; the other, eight months.

Requa knows very well that Metro can modify its three-year contract with Orion, which makes CNG buses. We obtained a copy of a presentation Metro was supposed to make at its board’s Operations Committee April 13. At its conclusion, Metro said it would explore the possibility of modifying its contract to buy diesel-electric hybrid buses as a part of its 100-bus order for 2001. (These buses, at $450,000 each, cost at least 50 percent more than conventional diesel buses.)

6. In the article, Requa alluded to CNG-related explosions and fires and alleged that the technology presents serious safety problems. In fact, CNG is just as safe as diesel, according to the Department of Energy. All types of motor vehicles, regardless of fuel type, are involved in accidents and crashes, and experience fires. Motor vehicle fuels burn; that’s where they get their energy. All motor fuels—gasoline, diesel, natural gas, electricity, ethanol, or hydrogen—can be dangerous if handled improperly. In 1997, for example, there were 208 diesel bus fires and 11 diesel fueling station fires, according to the Department of Transportation.

The bottom line is, Metro plans to continue to buy conventional diesel buses until fuel-cell technology is available, which will be at least 10 years down the road. Meanwhile, Washington metro residents will continue to breathe toxic diesel exhaust. Studies consistently demonstrate that exposure to diesel exhaust for 10 years or more significantly increases the incidence of lung cancer. What’s the cost of that?

Natural Resources Defense Council

Mark Wenzler

Sierra Club New Columbia Chapter