EPA Proposes Cut in Diesel Sulfur Level

WASHINGTON — The Environmental Protection Agency, extending a California pollution standard to the rest of the nation, Monday proposed slashing sulfur levels in diesel fuel to reduce acid rain and airborne carcinogens.

The measure, subject to final agency approval, would require fuel refiners to reduce the sulfur content of diesel fuel to .05% from current average levels of about 0.25% beginning Oct. 1, 1993. The proposed EPA standard is similar to a recently enacted California law.

The proposal appears to have widespread support. The reduced sulfur standard is based on recommendations from refiners and diesel engine manufacturers, and it has been endorsed by many environmentalists.

When sulfur is combined with oxygen during combustion in a diesel engine, soot-like particulates and sulfur dioxide gas are released into the atmosphere. Both emissions are known to be environmental hazards: Soot can cause lung damage when inhaled, and sulfur dioxide is the major cause of acid rain.

“This is an important discretionary step EPA can take to reduce acid rain by lowering sulfur dioxide emissions,” said EPA Administrator William K. Reilly in a statement.

Soot from diesel engines “remains a serious air-quality problem for many urban areas. Heavy-duty diesel engines are a major source of particulate emissions, including the smaller, fine particles that are of greatest concern in protecting public health,” Reilly said.

“The rule’s most important contribution is that it will reduce particulate emissions in the urban atmosphere,” said Bob Yuhnke of the Colorado office of the Environmental Defense Fund, an environmental group. Yuhnke said that particulates are “one of the most cancerous pollutants in the urban air.”

Even so, the proposal does not go as far as a new California law to reduce other kinds of diesel emissions, Yuhnke said. The EPA proposal would cap emissions of diesel fuel aromatics, a pollutant that contributes to urban smog, at current levels. But the California law, which went into effect last month, requires reductions in aromatic emissions, he said.

The EPA’s sulfur standard will bring about a 15% to 20% reduction in overall particle emissions, Yuhnke said.

The EPA had been considering its new rule for several years, but it did not have support from the Ronald Reagan Administration, according to a congressional aide. The agency’s decision to adopt the rule shows that the Bush Administration has placed a higher priority on combatting acid rain, the aide said.

The proposal will be “a helpful step” in curbing acid rain, the aide said.

Although the new federal rule has essentially the same sulfur standard as the California law, an EPA spokesman said that the agency did not use the state law as a model. Instead, the agency based its regulation on an unusual plan devised last year by diesel engine manufacturers and oil refiners.

Susan Hahn, spokeswoman for the American Petroleum Institute, said that the trade group is “encouraged” that the EPA proposal appears to have adhered to the recommendations made last summer by API, the National Petroleum Refiners Assn., the Engine Manufacturers Assn. and the National Council of Farmer Cooperatives.

If the rule receives final agency approval, it could raise the price of diesel fuel about 2 cents a gallon and cost fuel refiners up to $910 million by 1995, the EPA said. But lower sulfur levels could prolong the life of diesel engines, resulting in significant consumer savings, the agency added.

The EPA has set aside 30 days for public comment on the rule, after which the agency is expected to take final action on the proposal.