How much mtbe in gasoline

At room temperature, MTBE is a volatile, flammable and colorless liquid that dissolves rather easily in water. MTBE had been used in U. Between and , MTBE had been used at higher concentrations in some gasoline to fulfill the oxygenate requirements set by Congress in the Clean Air Act Amendments. A few cities, such as Denver, used oxygenates MTBE at higher concentrations during the wintertime in the late 's. Oxygen helps gasoline burn more completely, reducing harmful tailpipe emissions from motor vehicles.

In one respect, the oxygen dilutes or displaces gasoline components such as aromatics e. In another, oxygen optimizes the oxidation during combustion. Most refiners have chosen to use MTBE over other oxygenates primarily for its blending characteristics and for economic reasons. Refiners could choose to use other oxygenates, such as ethanol. The two oxygenated gasoline programs were:. Nearly all of these results were nondetections, while sources had two or more MTBE detections.

Nationwide, the data on the presence of MTBE in drinking water have been more limited. Most MTBE concentrations ranged from 0. This survey monitored sources of drinking water for randomly selected community water systems including samples from groundwater-supplied systems and samples from surface-water-supplied systems. MTBE was found in 8. The researchers found MTBE in Looking at ground water generally not only drinking water wells , the data indicate that low levels of MTBE are found often.

In all, MTBE was detected in ground water in 22 of the 42 states. The California Environmental Protection Agency has estimated that, based on monitoring information available for these sites, MTBE can be expected to be found in shallow, unused ground water at thousands of UST sites in the state, and often at high concentrations in the parts per million range. Safe Drinking Water Act Initiatives. In December , the agency issued a drinking water advisory for MTBE based on consumer acceptability for taste and smell.

EPA issues drinking water advisories to provide information on contaminants in drinking water that have not been regulated under SDWA. Specifically, the advisory states that. Compounds on the contaminant candidate list are categorized as regulatory determination priorities, research priorities, or occurrence priorities.

Thus, while EPA has not selected MTBE for regulation to date, the agency is pursuing research to fill the existing data gaps so that a regulatory determination may be made. The Safe Drinking Water Act also directed EPA to publish a rule by August requiring public water systems to conduct monitoring for a list of unregulated contaminants that may require regulation.

The occurrence data generated under the Unregulated Contaminant Monitoring Rule, combined with the results of ongoing health effects studies, are intended to provide information needed by EPA to make a regulatory determination for MTBE. Under SDWA, the next round of regulatory determinations will be made in EPA typically requires roughly three and one-half years to promulgate a drinking water regulation; thus, the earliest EPA would be expected to issue a drinking water regulation for MTBE is Underground Storage Tank Regulation.

Under this program, EPA has set operating requirements and technical standards for tank design and installation, leak detection, spill and overfill control, corrective action, and tank closure. As of , all tanks were required to comply with leak detection regulations. Additionally, all tanks installed before December when standards for new tanks took effect were required to be upgraded, replaced, or closed by December 22, Federal and state regulators anticipate that as tank owners and operators comply with these requirements, the number of petroleum and related MTBE leaks from UST systems should decline significantly.

However, MTBE has been detected at thousands of leaking tank sites, and this additive is proving more difficult and costly to remediate than conventional gasoline. A key concern for states is that, as testing increases, it is likely that the number and scope of needed cleanups may increase as well. These provisions created the LUST Trust Fund and authorized EPA and states to use the fund to clean up underground storage tank spills and leaks in cases where tank owners or operators do not clean up sites.

EPA and states use the annual trust fund appropriation primarily to oversee and enforce corrective actions performed by responsible parties. EPA and states also use fund monies to conduct corrective actions where no responsible party has been identified, where a responsible party fails to comply with a cleanup order, or in the event of an emergency, and to take cost recovery actions against parties.

Since the federal underground storage tank program began, nearly 1. Through FY, , tanks subject to UST regulations remained in service, , releases had been confirmed, , cleanups had been initiated, and , cleanups had been completed.

As part of its effort to gather information and focus research, in November , EPA established an independent Blue Ribbon Panel on Oxygenates in Gasoline to review the broad range of issues posed by the use of MTBE and other oxygenates. The panel was established under the auspices of the Clean Air Act Advisory Committee, and its membership reflected a broad range of experts and stakeholders. The panel's numerous water protection recommendations addressed prevention, treatment, and remediation.

For example, the panel recommended that EPA work with Congress to determine whether above-ground petroleum storage tanks which generally are not regulated should be regulated; work to enhance state and local efforts to protect lakes and reservoirs that serve as drinking water supplies by restricting use of recreational watercraft; and accelerate research for developing cost-effective drinking water treatment and remediation technologies.

The panel also suggested that EPA and others should accelerate ongoing health effects and environmental behavior research of other oxygenates and gasoline components that would likely increase in use in the absence of MTBE. She also stated her commitment to work with Congress for "a targeted legislative solution that maintains our air quality gains and allows for the reduction of MTBE, while preserving the important role of renewable fuels like ethanol.

Recognizing that this process could take several years to complete, she renewed her call for congressional action to "amend the Clean Air Act to provide the authority to significantly reduce or eliminate the use of MTBE," to "ensure that air quality gains are not diminished," and to "replace the existing oxygen requirement contained in the Clean Air Act with a renewable fuel standard for all gasoline. Actions taken by the state legislature and the governor helped propel the issue to national prominence.

Legislation signed October 8, , required the state to set standards for MTBE in drinking water, and required the University of California to conduct a study of the health effects of MTBE and other oxygenates and risks associated with their use. This date was amended, in March , to December 31, EPA for a waiver from the requirement to use oxygenates in reformulated gasoline and required three state agencies to conduct additional research on the health and environmental impacts of ethanol, the most likely substitute for MTBE.

Without a waiver, gasoline sold in ozone nonattainment areas in the state was required to contain another oxygenate once the MTBE ban took effect. Following California's decision to phase out MTBE, at least 24 other states have acted to limit or phase out its use. Table 2 summarizes state actions to ban MTBE. Table 2.

The major potential alternatives to MTBE are other oxygenates. Oxygenates possess several advantages, including high octane and the ability to replace toxic components of conventional gasoline. These other oxygenates may pose health and environmental impacts, but inadequate data make it difficult to reach definite conclusions.

Ethanol and other alcohols are considered relatively innocuous on their own; they generally do not persist in ground water and are readily biodegraded. However, research suggests that the presence of ethanol in a gasoline plume can extend the spread of benzene and other toxic constituents of gasoline through ground water. In announcing the phaseout of MTBE in his state on March 25, , California's Governor Davis required three state agencies to conduct additional research on the health and environmental impacts of ethanol, the most likely substitute.

In reports approved in January , the agencies concluded that if ethanol were substituted for MTBE, there would be "some benefits in terms of water contamination" and "no substantial effects on public-health impacts of air pollution. A more recent article, based on the California ethanol review, focused specifically on the relative risks of ground water contamination by spills of ethanol-blended gasoline, MTBE-blended gasoline, and non-RFG gasoline.

The authors concluded that. The switch from MTBE to ethanol is not without technical problems, as well. Ethanol costs substantially more to produce than MTBE; and it poses challenges to the gasoline distribution system it separates from gasoline if transported long distances by pipeline, so it must be mixed with non-oxygenated gasoline blendstock close to the market in which it is to be sold.

Since , some refiners have discussed the possibility of making gasoline that meets the performance requirements for RFG without using oxygenates. Now, with the enactment of the Energy Policy Act of , which ends the oxygenate requirement in May and imposes a renewable fuels requirement for gasoline, refiners generally are choosing to use ethanol to replace MTBE. Temporarily, this has led to shortages of ethanol and has contributed to higher gasoline prices in March and April Ethanol producers, represented by the Renewable Fuels Association RFA , assert that these shortages are temporary: million gallons of additional annual capacity are expected online before July, , according to RFA, and another million gallons by the end of the year.

With additional imports from Brazilian and Caribbean suppliers, reallocation of ethanol within the marketplace, and the use of ethanol stored at terminals in anticipation of the transition, RFA says, " The increased demand for ethanol has stimulated the market for corn.

Federal tax credits for ethanol blending and other state and federal legislation have played key roles in promoting this growth.

The bill passed the House April 21, ; a different version passed the Senate June 28, The House bill would also have provided a "safe harbor" from product liability suits for MTBE producers. Conferees on the legislation could not reach agreement on most of these provisions, so the version of H. As a result, controls on the use of MTBE and liability for cleanup of MTBE in ground water and drinking water will be left to the states and the courts respectively.

The reasons why these provisions were left out of the final version are complicated. The conferees faced time pressure as the result of a White House demand that energy legislation be delivered to the President by August 1. For that deadline to be met, the conferees needed to reach agreement on a range of issues quickly. The safe harbor and the provisions on the phaseout of MTBE, described in more detail below, were not amenable to a quick compromise.

Thus, the path of least resistance was to remove them. However, the enacted bill will also require a substantial increase in the use of renewable fuels, such as the competing oxygenate, ethanol, in both conventional and reformulated gas.

With ethanol use required, there will be less need for gasoline refiners to use MTBE. Refiners began reacting to these provisions almost immediately: Valero Energy, the nation's largest petroleum refiner, announced August 2, , that it will discontinue production of MTBE in May , when the RFG oxygenate requirement is eliminated.

The remainder of this section discusses the principal features of the House and Senate bills and how they were addressed in the enacted legislation. Safe Harbor Provision. Perhaps the most controversial element in H. The effect of the House provision would have been to protect anyone in the product chain, from manufacturers to retailers, from liability for damages for contamination related to MTBE and renewable fuels, or for personal injury or property damage based on the nature of the product.

The safe harbor provision would have applied retroactively to September 5, , potentially barring lawsuits filed on or after that date, including those filed by the State of New Hampshire and numerous cities, towns, counties, municipal water suppliers, and schools.

Prior to that date, five lawsuits had been filed. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Fuel Efficiency. Fuel Consumption. What is the problem with MTBE in gasoline? MTBE gets added to gasoline for two reasons: Advertisement. It boosts octane see this Question of the Day for a discussion of octane. It is an oxygenate, meaning that it adds oxygen to the reaction when it burns see this Question of the Day for a discussion of oxidizers.

Ideally, an oxygenate reduces the amount of unburned hydrocarbons and carbon monoxide in the exhaust.