State Board OKs Plan to Cut Emissions on Benzene

Signaling the start of a wider attack on air pollution, the state Air Resources Board on Thursday moved to impose controls on an air contaminant solely on the basis that it causes cancer.

On an 8-0 vote, the board adopted the outline of a plan to control emissions of benzene, used in gasoline as a substitute for octane-boosting lead. The rules to be developed by the board in the next three years could mean a motor vehicle emission standard for benzene and restrictions on its use as an additive. The plan also recommends tougher controls on refinery emissions.

Previous emission controls, including those on motor vehicles and on the amount of lead allowed in gasoline, have been based on other kinds of documented health consequences, such as respiratory and heart problems.

Benzene is a natural component of crude oil. It is also formed during the refining of gasoline and in gasoline combustion in motor vehicle engines. It has long been associated with cancer, particularly leukemia.

While the benzene control plan does not immediately identify specific rules to control benzene emissions, it is considered a blueprint for the kinds of controls that the board will adopt in the next three years. It may be several more years, however, before the controls are actually in effect.

Airborne Chemicals

If benzene levels are reduced, a board spokesman said, petroleum companies may have to refine crude oil more extensively to boost fuel-octane levels. The more it is refined, or distilled, the higher the octane, he said.

Benzene is the first of 47 airborne chemicals that are being studied to determine if they should be considered toxic air contaminants that cause cancer. Once identified as a toxic air contaminant, control plans similar to the one adopted Thursday for benzene would be drafted to regulate emissions of the other pollutants.

The board is scheduled today to consider adding dioxins to the official list of air toxics.

“All of our anti-smog standards are designed to protect public health and prevent health damage, but these will be the first controls that are justified solely on benzene’s ability to cause cancer,” board spokesman Bill Sessa said.

Setting of such standards were required by the enactment in 1983 of legislation authored by Assemblywoman Sally Tanner (D-El Monte).

Benzene is present in greater concentrations in the South Coast Air Basin than any other area of the state. A report to the air board indicated that annual average concentrations in the basin are 4.2 parts per billion, as contrasted with a statewide average of 3.3 ppb. The comparable figure along California’s north coast is 0.8 ppb. It is 3.0 in the San Francisco Bay Area, 2.7 ppb in San Diego and 3.5 ppb at Lake Tahoe.

Without the air board plan, existing regulations, chiefly auto emission standards, are expected to reduce existing levels of benzene 29% over the next 15 years. However, air board Chairwoman Jan Sharpless said Thursday, “. . . We believe more can be done to reduce the cancer-causing potential of this chemical.”

If all the plan’s proposals were put into effect, benzene reductions would be cut by 50% over the next 15 years.