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MTBE Litigation - Background


Those who spill or leak gasoline – with or without MTBE – are required by law to clean it up.  If they do not do so, litigation may be appropriate.  In the past few years, a different type of lawsuit has emerged; one which seeks to bypass this “spiller pays” rule and, instead, hold the oil industry liable for putting MTBE in gasoline in the first place.  The lawyers who have filed these cases claim that gasoline containing MTBE is a defective product.  It is not.  MTBE did what it was supposed to do, help clean the air.  It is wrong to sue companies for following the directive of Congress to add an oxygenate like MTBE to gasoline, when Congress and the EPA expected and intended MTBE to be used to fulfill that mandate.

This Web site is intended to assist the media in understanding MTBE litigation and the issues underlying the litigation. If you have any questions, please call (866) 280-0313.


In 1990, Congress amended the Clean Air Act to require that gasoline sold in areas with significant air pollution contain an oxygenate. Adding oxygen to gasoline promotes more complete combustion of the gasoline, and cuts down on air pollution. At that time, Congress and the EPA knew that MTBE would be the primary oxygenate used given supply, transportation and other difficulties with using alternatives such as ethanol.  (By now, however, MTBE has been out of use in gasoline for a number of years, which is why some statistics regarding its use have become dated.)

There were two programs under the Clean Air Act that required the use of oxygenated fuel: a winter oxyfuel program in cities with elevated levels of carbon monoxide and a year-round Reformulated Gasoline (RFG) program in cities with the worst ground-level ozone (smog). Reformulated gasoline containing an oxygenate such as MTBE is required in as much as 30% of the entire country’s gasoline supply. 

Although use of MTBE was not expressly mandated, refiners used it in most markets because it was the only practical option given supply, cost and transportation issues. Congress expected and intended the industry to rely on MTBE to comply with its directive. 

MTBE Did What It Was Suppose To Do - It Cleaned The Air

MTBE worked.  Using gasoline oxygenated with MTBE, as opposed to non-oxygenated conventional gasoline, reduced emissions of carbon monoxide and other pollutants, and reduced public exposure to ambient carbon monoxide and ozone.

It has been estimated that in 2002, the use of oxygenates in gasoline – primarily, the use of MTBE – reduced summertime emissions of air pollutants like volatile organic compounds (VOCs) and oxides of nitrogen (NOx) by 2,200-2,300 tons per day relative to the use of 1990 conventional gasoline.  (VOCs and NOx are ozone precursors.)  In the New York City Metropolitan Area alone, the use of MTBE in 2002 has been estimated to have reduced those emissions by more than 120 tons per day, which translates to removing, in that metro area alone, more than one million vehicles from the roads.  As the EPA has noted, millions and millions of Americans breathe cleaner air because of RFG.

In fact, in regards to reducing air pollution, MTBE is even more effective than other oxygenates.  MTBE is similar to other ethers, though generally less photochemically reactive and with a better blending octane rating.  There are significant differences, however, between MTBE and alcohol oxygenates like ethanol and TBA.  For example, the addition of an alcohol oxygenate causes fuel to evaporate more readily, an effect that is especially pronounced when alcohol-oxygenated gasoline is commingled with non-oxygenated or ether-oxygenated gasoline, a frequent occurrence.  In addition, alcohol-oxygenated gasoline tends to have a much higher rate of permeating the containers in which it is stored or transported, increasing evaporative emissions.  MTBE, on the other hand, effectively reduces air pollution with fewer such pitfalls.


But along with its air cleaning benefits, use of MTBE involves tradeoffs.  MTBE can give drinking water an unpleasant taste and odor at certain concentrations when gasoline containing it is released into the environment, and the MTBE reaches groundwater used to provide water for consumer purposes. When the federal government effectively mandated the use of MTBE in 1990, it knew the risk the additive posed to groundwater. See related link: Federal Government’s Knowledge of MTBE’s Risks to Groundwater When the Government Required Its Use

Prior to the enactment of the 1990 Mandate, EPA had completed a two-year review of the risks MTBE posed to the environment and to human health. With extensive information about actual and potential environmental impacts, EPA again approved the use of MTBE in gasoline. The federal government made the decision to effectively require the use of MTBE despite its well-known risks to groundwater. 

Instances of MTBE impacts on drinking water have decreased significantly in recent years for two reasons. First, most old steel underground storage tanks have been replaced as a result of an EPA mandate requiring tanks to be upgraded by 1998. And gasoline releases are being cleaned up – under stiff federal and state laws requiring those who release gasoline into the environment, with or without MTBE, to clean it up.

According to EPA, the number and extent of gasoline releases have steadily declined in recent years. In an EPA report released in November 2004, the agency reported that the number of confirmed releases dropped 35 percent from 2003, and the number of sites requiring remediation was down five percent from 2003.


Moreover, the detection of MTBE in drinking water is quite rare.  The EPA has advised that an MTBE threshold level of 20-40 parts per billion (“ppb”) is sufficient to avoid taste and odor concerns and to render water fully potable.  From 2000 to 2005, the EPA collected MTBE sampling data in finished drinking water from (1) all large public water systems nationwide, and (2) a nationally representative subset of small public water systems.  From the 34,000 samples, MTBE was detected above 5 ppb (the minimum reporting level for the study) in only 26 samples – or less than 0.1% – and above 20 ppb (the minimum threshold for taste or odor issues) in only five samples – or less than 0.015%.

The EPA’s findings are supported by those of numerous other studies.  A recent U.S. Geological Survey contained all MTBE sampling data collected though the National Ambient Water-Quality Assessment from 1993 through 2002.  That survey detected MTBE above 20 ppb in only one sample among the nearly 4,000 untreated groundwater wells studied.  In California, where the California Department of Public Health (CDPH) maintains a database containing drinking water monitoring results for contaminants, 15,000 California drinking water sources have been sampled for MTBE from 1997 through mid-2009.  Among those samplings, according to the CDPH, “nearly all of the results are non-detects” for MTBE.  Only 0.2% of the samples detected a peak level greater than California’s primary “maximum contaminant level” (MCL)—which, at 13 ppb, is still far lower than the EPA’s taste-and-odor threshold.


Notwithstanding this fact, an enterprising group of trial lawyers has convinced some water providers and state and local governments to sue the oil industry for using MTBE in gasoline – despite the fact that Congress effectively required it.

In the majority of the cases filed, the levels of MTBE present in groundwater are negligible or nonexistent.  Frequently, the cases are based on old detections, or detections well below EPA levels.  Several MTBE cases have been dismissed.  Others have resulted in settlements that reflect the expense and distraction of defending litigation of this sort.  In one case brought by the City of New York, the case went to a verdict in favor of the City versus a single oil company defendant.  The jury in that case found that ethanol was not a feasible alternative to MTBE yet nonetheless found for the City; the verdict is being appealed.  Lawsuits against oil companies for making and marketing gasoline containing MTBE are wrong. It is inappropriate to hold companies liable for using MTBE when the federal government effectively mandated its use.


Related Links

Click here to read a history of the use of MTBE

Click here to read more about the Federal Government's Knowledge of MTBE's Risks to Groundwater When the Government Required Its Use


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