f e a t u r e  s t o r y

Diesel Fuel Exonerated

Regulators, environmentalists and trucking industry reach compromise in battle to declare diesel a killer.

Deborah Lockridge
Senior Editor

The California Air Resources Board, the trucking industry and environmentalists finally reached a compromise in a nine-year battle over the state’s efforts to declare diesel exhaust a carcinogen.
     In its ruling in late August, CARB declared 40 chemicals found in diesel fumes to be toxic air pollutants. These chemicals are found in diesel exhaust as particulates, which already have been reduced 90% over the last 12 years, thanks to federal emissions regulations.
     The trucking industry breathed a sigh of relief, because the resolution did not condemn diesel fuel as a whole and admitted that the studies CARB was using to determine human exposure were outdated.
     Joel Anderson, of the California Trucking Assn., says the decision “reflects the concessions we’ve asked for all along.” However, the American Trucking Assns. was not quite as positive. Although the decision is a “marked improvement” over the earlier proposal, Walter McCormick, ATA president and CEO, said “the decision still leaves important questions unanswered.”
     “CARB failed to reconcile the inconsistency between the way in which the federal EPA and CARB interpret the same scientific studies,” McCormick says. Earlier this year, ATA says, an independent panel of federal EPA scientific advisers, reviewing the same evidence as CARB, rejected findings of a relationship between diesel exhaust and cancer.
     Like the CTA, the Engine Manufacturers Assn. praised the compromise. “We actually think that it validates some of the work we have done in the past nine years or so with regulators to get them to focus on the particulate matter issue,” says Charlie Souhrada, spokesman for EMA. “That work has helped us reduce the particulate matter to the tune of 90%. The resolution focuses on the remaining 10%.”
     One of the trucking industry’s concerns was that a ruling that diesel exhaust was a carcinogen opened the industry to lawsuits. However, the compromise seems to have alleviated many of those fears.
     “What would have been a crushing blow to the industry would have been a listing of the whole exhaust,” says CTA spokesman Beau Biller, “because the only way to eliminate exposure to the whole exhaust is to eliminate it. We have the technology to improve the particulate emissions.”
     In addition to targeting specific particulates, rather than diesel exhaust in general, CARB modified its findings to state that there is only an “association” of health effects from exposure to diesel exhaust, rather than a “causal link.”
     And what exactly that association may be is unclear, as well. Studies reviewed by state officials were of questionable relevance. One studied the health problems of railroad workers during the 1940s and 1950s. “So they’ve said, we think it’s bad for you based on old stuff, but we don’t know how [today’s engines and clean California diesel fuel] affect people’s exposure,” Biller says.
     Souhrada says, “We still don’t know” if there’s a relationship between diesel exhaust and cancer.
     That fact was borne out by a court decision only days before the CARB resolution. California Superior Court Judge David Garcia threw out a lawsuit by the Corporation for Clean Air against a number of engine manufacturers under Proposition 65, which requires businesses that expose people to carcinogens to warn them about the danger. “I see absolutely no admissible evidence in this case … that would create a triable issue of fact, just on the question of whether or not there is significant risk,” the judge found.
     According to Souhrada, research on any possible link between diesel exhaust and cancer is being conducted by the independent Health Effects Institute in Massachusetts. Sponsored in part by industry, environmental groups and regulators, the research “will hopefully provide us the answers we need as to what the health effects of diesel exhaust may be and what additional work we may need to do,” he says.
     The next step for California is for officials to come up with a plan to limit human exposure to the chemicals, including benzene and dioxin, including setting limits for the emissions of each one. This process will probably take years. CARB voted to create a working group of health experts, industry leaders and environmentalists who will help devise plans.
     In fact, Biller says, the group may find that today’s “smokeless” trucks already have virtually eliminated the risk associated with diesel exhaust. Future regulations could include requiring even cleaner-burning engines or alternative fuels, such as compressed natural gas. But diesel will still be a viable fuel. “A ban on diesel fuel or diesel engines would not be considered,” CARB said in a statement. More than 2 billion gallons of diesel fuel is burned each year in California, according to CARB.
     Complicating the state’s attempt to require cleaner-burning fuels is the fact that about half the diesel consumed in California is purchased out of state. CTA says it supports efforts for national diesel fuel conformity. “It’s time for every truck on the road to be smokeless, whether it’s based in California or not,” Anderson says.
     California is the first state to make such a ruling, but chances are it won’t be the last. CARB is one of the most influential environmental regulatory agencies in the country. Its decisions often serve as a bellwether for stricter standards not only in other states, but also at the federal level.
     “The EPA is going to be giving increased scrutiny to diesel emissions from heavy duty trucks,” says Daniel Greenbaum, president of the Health Effects Institute.