WASHINGTON - To say sulfur in fuels was the underlying theme of the 1998 Society of Automotive Engineers Industry/Government meeting here in May would be an understatement.

It was rare for a speaker not to at least draw reference to the tailpipe emission problems caused by sulfur in gasoline, regardless of the overall topic, during the meeting of policy wonks from automotive companies, consumer groups and government agencies.

In fact, one of the speakers at the automotive pow-wow was Red Cavaney, president and CEO of the American Petroleum Institute. In tune with the sulfur lynch-mob mentality of the meeting, much of Mr. Cavaney's talk centered on defending the API position on sulfur in fuels against the more aggressive calls to action from the auto industry.

Engineers and regulators also crossed rhetorical swords over the future of diesels in passenger cars and the need to treat trucks more like cars when new federal tailpipe emission laws are written later this year.

The SAE Government/Industry meeting is an annual opportunity for regulators and regulated at the staff level to get together and debate issues and search for common ground. It's an often contentious series of meetings over three days as engineers and scientists jockey for the "good science" high ground on complicated political issues.

Sulfur in fuels

Everyone in the debate, even the API, agrees that sulfur in fuel degrades the performance of emission catalysts. Sulfur is found naturally in crude oil and carries through into gasoline unless specifically removed.

The debate swirls around what level of sulfur is low enough to make engines run cleaner yet won't impose undue burdens on the oil industry. The U.S. Environmental Protection Agency (EPA) deems it so important that a whole separate report on the issue was released as part of the Tier 2 study. Tier 2 is the bureaucratic name for the next level of federal tailpipe emission regulations likely to be finalized this year to take effect in 2004.

The sulfur fuel players met in mid May again specifically to discuss the sulfur-in-fuel issue, although attendees say the meeting did little more than spell out the conflicting opinions of the debate.

Current levels of sulfur in gasoline in most of the U.S. average about 300 parts per million (ppm), with about one-quarter of the supply as high as 500 ppm. California requires much lower concentrations, with a maximum of 80 ppm and an annual average of 30 ppm to help clean up the polluted air.

The API wants to go with a two-tier system requiring 150 ppm during summer in areas with air pollution problems and 300 ppm in the winter for polluted areas, and year-round in areas without problems.

The API plan would roll out in 2004, in time for the next round of federal tailpipe emission requirements.

The auto industry is proposing that the whole country adopt the California standard and that the requirements be rolled out as soon as possible. The automakers are pointing to the impact of sulfur on the so-called National Low Emission Vehicle (NLEV) program. NLEV is a voluntary program that will bring cars to 45 states by 2001 that are capable of operating with lower emissions than the government can mandate.

But without sulfur reform, automakers warn, the NLEV program will end up being a waste of time because many of the NLEV vehicles won't be able to meet new air pollution requirements burning normal sulfur fuel.

The EPA initially estimated that NLEV standards would produce vehicles 70% cleaner than the current federal standards allow in the 49 states outside of California. But now the EPA admits those estimates were optimistic in light of recent tests of NLEV vehicles burning gasoline with average sulfur levels.

The regulators now expect the real benefit to be much lower. Tests by automakers and the API support that more gloomy outlook.

The API plan is expected to cost about 1 or 2 cents a gallon, while the automakers' plan is closer to 5 cents per gallon. But new proponents of emerging technology suggest it will be half as expensive to remove sulfur from fuel in the future, even at the stricter automakerlevels.

There still is a chance of an industry compromise, however.

Mr. Cavaney says ultimately that the best route is for the auto and oil industries to hash out an agreement themselves - with refereeing from regulators, rather than be subjected to government edicts.

Although the auto industry may seem to have the upper hand at the moment, the API chief cautions not to count his industry out.

"They've had their plan out for a while. We're just getting started. Let's not forget the political aspects of this debate," Mr. Cavaney says. "After all, we're talking about raising fuel prices. People don't like it when you start talking about raising fuel prices."

The death of diesels, part 2

Engineers at the SAE meeting say they are beginning to worry that diesel engines for passenger cars will be crowded out by competing technologies because of continuing emission challenges.

Last year the best and the brightest were raising the warning flag because of strict rules in California that all but eliminate diesels there in the next few years.

The diesel clearly is considered "high risk" to meet emission requirements with current technology, one engineer says. f course, sulfur in fuels also plays a role in that challenge, several engineers pointed out.

One prominent member of the Partnership for a New Generation Vehicle (PNGV) says that it's conceivable that gasoline direct-injection engines might be able to fill the interim technological needs prior to the maturation of fuel-cell technology, and diesels will be skipped in cars altogether.

It has been more than seven months since Clinton Administration officials made it clear that diesel engines would be expected to burn as cleanly as gasoline engines. That was seen as a turnaround from earlier PNGV guidelines that suggest diesel would be given some emission breaks in recognition of their much higher fuel economy.

However, experts remain confident there is a role for the compressed ignition direct injection engine in the light-truck arena, even if passenger-car efforts fail.