The MTBE bomb

Urgent message from U.S. refiners to state and federal governments: If you drop bombs in the area of fuel chemistry, pick good targets.

California Gov. Gray Davis dropped a bomb Mar. 25 when he ordered phased removal of methyl tertiary butyl ether (MTBE) from gasoline. Refiners use the substance chiefly to meet oxygen mandates for the reformulated fuel required in areas not meeting federal standards for ozone pollution. California has its own reformulation requirements, the nation's toughest.

Water concern

Davis acted out of concern for water quality. MTBE has entered aquifers in California and shown up in drinking water. Most occurrences have been at concentrations below the U.S. Environmental Protection Agency's advisory levels for taste and odor; nevertheless, worry about the additive has become intense.

EPA last year formed a group to study the possible health risks. But it sees water contamination by MTBE mainly as a problem of leaking storage tanks. So far, it has treated the oxygenate as a net environmental benefit due to its role in fuel reformulation.

As California goes on environmental regulation, however, so tends to go the rest of the U.S. The state's proposed ban on MTBE might easily turn national in scope. It thus might wipe out an industry supplying 90% of the oxygenate used in gasoline reformulated to federal and California standards and in wintertime fuel for regions with carbon monoxide pollution. For refiners and MTBE manufacturers, the move by Davis is indeed a bomb.

In his announcement, however, the California governor acknowledged a proper target. He supported efforts to waive the federal requirement for oxygen in reformulated gasoline, calling on state agencies to petition EPA for such a move and urging support for related legislation by his state's congressional delegation.

That's the right move. The benefit of oxygen in reformulated gasoline has long been subject to question. Gasoline chemistry is complex. Reformulation involves tradeoffs. Contrary to the sweeping "clean-burning" claims of oxygenate makers, not everything about oxygen additives works to the advantage of air quality.

In fact, a University of California study of MTBE on which Davis based his decision said, "There is no significant additional air quality benefit to the use of oxygenates such as MTBE in reformulated gasoline relative to alternative [California] nonoxygenated formulations."

The Oxygenated Fuels Association promptly pointed out that the study limited its findings to "advanced-technology vehicles," which the association says represent 5.5% or less of the California fleet. It naturally asserts great benefit from reformulating gasoline with oxygen.

But so what? Assertions by a group with a clear commercial interest shouldn't have the final say in policy. The policy must accommodate judgments about oxygen by the people who make gasoline.

For reformulated gasoline-gasoline prescribed in response to ozone smog problems-there should be no mandate for oxygen. Chemistry provides no clear justification for the mandate; in fact, the requirement is mainly a political favor to oxygenate makers, especially heavily subsidized ethanol manufacturers now eager to fill the market void promised by the ban against a commercially superior product.

Freedom to choose

This is not to say that refiners won't use oxygenate, including ethanol, in reformulated gasoline if MTBE disappears. Some of them probably will. But they should be free to make the choice. If they can reformulate gasoline to government specifications without oxygen, they shouldn't have to add oxygen to their product. To deny them use of MTBE and not give them that much flexibility would be indefensible.

At this point, refiners have no way to assess damage from California's bomb. Much depends on what happens at the federal level. The impact will soften if the blast destroys ill-advised oxygen mandates, too.