Fowler Associates Labs

The Oxygenated Fuels Mandate
The Hidden Safety Issue

By
Dr. Robert R. Swank Jr.
October 12, 2004

Unintended consequences are a constant reminder to policy-makers that however well-intended their schemes might be, something almost always gets overlooked. A case in point is an ambitious plan to provide for cleaner air in urban areas -- one embraced by Congress, the White House, and the US Environmental Protection Agency (EPA) over a decade ago -- that has now come back to haunt the American driving public.

Using the best science available to it at the time, EPA in the late 1980s concluded that any of several candidate gasoline additives containing oxygen (i.e., oxygenates), such as ethanol or ethers, could be effective in reducing tailpipe emissions of carbon monoxide (CO), hydrocarbons, and particulates. Indeed, model projections indicated that oxygenate use could bring many urban areas back into compliance with federal CO standards during the winter months, and help reduce summer urban smog and ozone problems as well. The US Congress reviewed and accepted EPA's findings and incorporated a fuel oxygenate requirement (approximately 2 to 3 percent by weight of oxygen) in the Clean Air Act amendments (CAA) of 1990.

With the oxygenate mandate in place, two candidates quickly emerged as the favorites to help provide American cities with cleaner air. The refining industry gave the nod to methyl tertiary butyl ether (MTBE), which could be profitably produced from certain waste parts of crude oil. Congress, on the other hand, by subsidizing the production of corn-based ethanol, smoothed the way for this oxygenate. Its supporters argued that ethanol, as a renewable resource, contributes to US energy independence and that its use also benefits American farmers.

The oxygenate mandate went into effect in 1995, and problems immediately surfaced. As early as 1987 and again in 1993, EPA scientists had warned that MTBE-blended fuel, when spilled or leaked, could contaminate ground and surface water in those areas of the country where it was in widespread use. And this is exactly what happened. Such was the uproar in communities affected by this contamination that EPA was eventually forced to ask Congress to phase out the use of MTBE. EPA's failure to heed the warnings of its own scientists on the use of MTBE, or to notify Congress of the potential problems with this oxygenate, is deeply troubling and underscores the need for substantial changes in the way the agency conducts its affairs. The fact that there is neither a scientifically defensible environmental assessment nor human health exposure-risk profile for what is arguably a better alternative to MTBE, ethyl tertiary butyl ether (ETBE), even though ETBE has been in use for almost a decade in the US and Europe, further underscores the need for improved procedures at EPA.

Even more serious is a safety issue that has arisen since the oxygenate mandate went into affect. Refueling fires at gas stations in the US have increased dramatically since 1995. Research conducted by the Petroleum Equipment Institute, American Petroleum Institute, and Fowler Associates, a South Carolina-based testing, training, and consulting firm, shows that the fires occur most frequently during the fall, winter, and spring when cooler, dryer air promotes the generation of static charges on people. Here's what can happen. When a customer pulls into a gas station on a cold, dry day, he gets out of the car and goes to the pump, inserts the fueling nozzle, and locks it on automatic. To escape the cold, he gets back into his car. After the nozzle clicks off, the customer gets out of the car and heads for the gas tank. Not realizing that a vapor cloud of volatile organic compounds (VOCs) from the fuel has formed around the nozzle and the filler opening of the vehicle, he reaches for the nozzle through the vapor cloud and his statically-charged body discharges its accumulated voltage via a spark. The result too often is a flash flame and a fire that maims or kills, and destroys vehicles and even gas stations. This scenario becomes more probable under the pressure of federal CAFE standards on the automobile producers. To meet the required mileage standards, manufacturers reduce vehicle weight by using more plastics and other insulating materials, including in the interiors, thereby elevating the possibility of significant static charge generation on the occupants. The National Highway Traffic Safety (NHTSA) Administration’s recent proposal to raise CAFÉ standards for “light trucks” – SUVs, minivans, and pickups – will force manufacturers to make additional weight reductions in these vehicles. If NHTSA’s proposal is allowed to stand, it will only contribute to the problem of refueling fires and will thus undermine NHTSA’s mission of providing for automotive safety.

To date, Fowler Associates has documented many such fires since the mid-1990s. Steve Fowler, the firm's president, strongly suspects this is but the tip of the iceberg because many incidents go unreported, or are lumped into the general category of "vehicle fires."

The growing number of refueling fires, like the MTBE water contamination problem, is another unintended consequence of the Clean Air Act amendments of 1990 and its mandated use of oxygenated fuels, especially gasoline and alcohol blends. Refiners blend these fuels for season-to-season use, and for distribution both in areas in compliance with federal air-quality standards as well as in areas with non-attainment status. During the summer, one major control on the volatility of the fuel is its Reid Vapor Pressure (RVP), which is capped to keep the fuel's VOCs to a minimum. Since ethanol increases fuel volatility when blended with gasoline, as compared to ETBE that significantly lowers it, the summer RVP cap can only be achieved in ethanol blends by removing volatile components from the gasoline itself via an extra, costly refining step. Nevertheless, the cap does help reduce volatile hydrocarbon emissions in urban areas and lowers the risk of summer refueling fires at the gas pump.

In contrast, during cooler seasons, refiners typically raise the RVP of fuel by increasing the levels of pentane and butane in the refined gasoline. This leads to better combustion performance in the fall, winter, and spring months. However, when ethanol is added to these fuels, the resultant RVP is much higher, perhaps too high. These very high, uncapped “winter” RVPs result in greatly increased amounts of VOCs escaping fuel tanks at the very time when static-spark formation potential is at its highest, thereby significantly elevating the risk of refueling fires.

What can be done to prevent the spreading of refueling fires? "We can begin by capping and reducing the fall, winter, and spring RVPs of blended fuels that would significantly cut the amount of escaping VOCs and thus lower the risk of refueling fires in cooler weather," says Mike Colburn, a California-based, independent fuel researcher who has spent years studying the issue.

Furthermore, Colburn notes that there is ample research showing how ethanol-blended fuels permeate and can reduce the effectiveness of elastomer components in today's state-of-the-art fuel supply and delivery systems. This poses an added potential safety hazard because fuel injection systems require high pressures and volumes to work properly.

Fixing this system that is definitely broken will require a thorough review of the whole issue of fuel formulation, including formulation effects on modern fuel systems and the associated risks of refueling and collision-related fires. This effort should involve all the key stakeholders, including the auto industry, the oil industry, EPA, and the Departments of Energy and Transportation. Up to the present, it appears that the automotive industry hasn’t always been recognized as a stakeholder in the issue of fuel formulation. That needs to change. The entire effort will likely entail reopening and reforming the Clean Air Act using updated science and common sense.

Moreover, in light of the problems that have resulted from the use of MTBE and ethanol, it is time to consider alternative oxygenates. Based on its properties, a prime candidate is ETBE. ETBE has about one-third the solubility of MTBE and, thus, represents a greatly reduced threat to groundwater in the event of blended fuel spills or leaks. In addition, ETBE is reported to provide twice the increase in octane rating and significantly greater reductions in tailpipe emissions of VOCs, nitrogen oxides, and carbon monoxide than ethanol. Furthermore, the reduced volatility of ETBE-gasoline blends is suitable for year-round use without costly gasoline refining adjustments for summertime weather, and represents a greatly reduced year-round potential of fire hazards associated with refueling and crashes.

And, because it's produced using ethanol, ETBE would also continue to benefit corn growers. In addition, converting ethanol to ETBE can be done at refineries using virtually the same equipment now used to make MTBE. This would preserve capital and keep the refining industry active in producing oxygenates. Moreover, blending at the refinery would save transportation costs and reduce overall environmental threats.

Of course, ETBE or any other alternative oxygenate should undergo strenuous testing and assessment to ensure that the unintended consequences that have followed in the wake of MTBE and ethanol are not repeated. Our collective failure to carry out such a comprehensive review when the 1990 CAA amendments were enacted has cost us dearly. It's time to take corrective action.

Robert R. Swank Jr., Ph. D., was a senior researcher and research manager over a 28-year career at the US Environmental Protection Agency.