■ Some evidence suggests that oxyfuels may increase emissions of other pollutants, especially nitrogen oxides. NOx is a major ozone precursor, and many areas participating in the oxyfuels program are also in nonattainment of the ozone NAAQS. (NRC 1996, 42-43)
■ Controversy exists over possible health effects from the use of MTBE, one of the most commonly used oxygenates. Studies indicated a 26-percent increase in formaldehyde and an 8-percent increase in benzene and 1,3-butadiene emissions because of MTBE. These substances are toxic. The National Research Council reported increased incidents of headaches, coughs, and nausea in some areas with oxygenate programs, although toxicity studies indicate that MTBE is not harmful at probable exposure levels. (NRC 1996, 18-19)
■ The possibility of groundwater being contaminated by gasoline containing MTBE is also a concern, as MTBE is more water soluble than gasoline. As yet, this chemical has only been found in very low concentrations in groundwater. Since MTBE levels are rarely monitored, it is difficult to determine whether this is currently a problem. (NRC 1996, 54-60)
● Reformulated Gasoline Program
The CAAA required nine areas that exceeded ozone NAAQS to implement an RFG program as of January 1995, and allowed other areas with ozone problems to "opt-in" to the program. Reformulation changes the amounts of various compounds present in the gasoline so that less criteria and toxic pollutants are emitted when it is burned.
The program will be phased-in in two stages. Phase I began in January 1995 and required that VOC and toxic air pollutants be reduced by 15 percent, and that NOx emissions not increase over 1990 baseline rates. Phase II, starting in the year 2000, will require a 25-percent reduction in VOC and a 20-percent reduction in toxics, as well as a 5.5-percent reduction in NOx. Both phases place a limit on the amount of benzene, a known carcinogen, allowed in fuel.
EPA estimates that Phase I of the RFG program will reduce VOC emissions by 90,000 to 140,000 tons during the summer period for all areas involved in the program. Phase II RFG standards are expected to reduce annual VOC emissions by an additional 42,000 tons, NOx emissions by about 22,000 tons, and total toxic emissions by 1,000 tons. (Federal Register 1994, 7810; USEPA 1993b)
According to EPA, Phase I is projected to cost $700 million to $940 million annually for those areas participating, while Phase II will cost an additional $133.4 million annually.12 Several studies have assessed the cost-effectiveness of the RFG program, and the general consensus seems to be that the program is comparable to other programs with similar objectives. (USGAO 1996, 4) Figure 4-12 shows EPA cost-effectiveness estimates for VOC.
12 Phase I estimate: 59 Federal Register 7810; Phase II estimate based on EPA cost-effectiveness estimates and estimated emissions reductions.
To date, no national study has been completed that demonstrates the impact of RFG on ozone levels. EPA has noted, however, that a greater proportion of sites in RFG-required areas showed significant decreases in average benzene and other highlighted mobile-related VOC concentrations than did sites in areas that did not use RFG.
Because of severe air pollution problems, California requires even cleaner blends of RFG than those required by federal standards. Preliminary findings by the California Air Resources Board (CARB) indicate a significant improvement in ozone and benzene concentrations coinciding with the use of federal Phase I gasoline in 1995.
