Health Studies Indicate MTBE Is Safe Gasoline Additive

Anderson, Earl V.

doi:10.1021/cen-v071n038.p009

Cited by 9 publications

(17 citation statements)

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“…In 1992, 1.8 billion gallons of MTBE was used in U.S. gasoline, an increase of 50% over the year before. 9 Both the U.S. Environmental Protection Agency (EPA) and the Health Effects Institute have provided thorough reviews and assessments of the hazard posed by MTBE. 1,10 Much of the recent exposure and health effects research concerning MTBE was precipitated by community complaints of odor and acute effects upon introduction of MTBE in oxyfuels or in reformulated gasoline.…”

Section: Introductionmentioning

confidence: 99%

Body Burden Measurements and Models to Assess Inhalation Exposure to Methyl Tertiary Butyl Ether (MTBE)

Buckley

Prah

Ashley³

et al. 1997

Journal of the Air & Waste Management Association

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Biomarkers of methyl tertiary butyl ether (MTBE) exposure and the partitioning of inhaled MTBE into the body were investigated in a human chamber study. Two subjects were exposed to an environmentally relevant nominal 5,011 µg/m 3 (1.39 ppm) MTBE for 1 hour, followed by clean-air exposure for 7 hours. Breath and blood were simultaneously sampled, while total urine was collected at prescribed times before, during, and after the exposure. Mass-balance and toxicokinetic analyses were conducted based upon the time series measurement of multiple body-burden endpoints, including MTBE in alveolar breath, and MTBE and tertiary butyl alcohol (TBA) in venous blood and urine.The decay of MTBE in the blood was assessed by fitting the post-exposure data to a 2-or 3-exponential model that yielded residence times (τ) of 2-3 min, 15-50 min, and 3-13 h as measured by alveolar breath, and 5 min, 60 min, and 32 h as evaluated from venous blood measurements. Based on observations of lower than expected blood and breath MTBE during uptake and a decreasing blood-to-breath ratio during the post-exposure decay period, we hypothesize that the respiratory mucous membranes were serving as a reservoir for the retention of MTBE. The decay data suggest that 6-9% of the MTBE intake may be retained by this non-blood reservoir. The compartmental modeling was further used to estimate important parameters that define the uptake of inhaled MTBE. The first of these parameters is f, the fraction of C air exhaled at equilibrium, estimated as 0.60 and 0.46 for the female and male subject, respectively. The second parameter is the blood-tobreath partition coefficient (P) estimated as ~18. The product of these parameters provides an estimate of the blood concentration at equilibrium as 8-11 times the air concentration. Blood TBA lagged MTBE levels and decayed more slowly (τ = 1.5-3 h), providing a more stable indication of longer term integrated exposure. The concentration ranges of MTBE and TBA in urine were similar to that of the blood, ranging from 0.37 to 15 µg/L and 2 to 15 µg/L, respectively. In urine, MTBE and TBA by themselves bore little relationship to the exposure. However, the MTBE:TBA ratio followed the pattern of exposure, with peak values occurring at the end of the exposure (20-and 60-fold greater than pre-exposure values) before decaying back to preexposure levels by the end of the 7-h decay period. Urinary elimination accounted for a very small fraction of total MTBE elimination (<1%). IMPLICATIONSHuman exposure to MTBE has become pervasive due its use as a fuel oxygenate in response to provisions of the Clean Air Act Amendments of 1990. Furthermore, there are concerns that MTBE poses a health hazard. Risk assessment and management provide the means by which MTBE's hazard will be evaluated and managed. The current study reduces the uncertainty in MTBE exposure assessment by measurements and models that define the relationship between exposure to a concentration of MTBE in air and the resulting body burden. Model parameters, inc...

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Section: Introductionmentioning

confidence: 99%

Body Burden Measurements and Models to Assess Inhalation Exposure to Methyl Tertiary Butyl Ether (MTBE)

Buckley

Prah

Ashley³

et al. 1997

Journal of the Air & Waste Management Association

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“…It is in this context that compounds such as MTBE are considered oxygenates,2 even though they may have other properties and uses (Anderson 1993).…”

Section: The Programsmentioning

confidence: 99%

“…After that date, all gasoline sold year-round in the nine large metropolitan areas with the most serious ozone problems must contain a minimum of 2.0 wt% oxygen. Other areas with ozone problems may choose to use the reformulation program (Anderson 1993). …”

Section: The Programsmentioning

confidence: 99%

Interaction between Titles 2 and 3 of the Clean Air Act as amended, 1990

Szpunar¹

1996

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“…[2] A typical gasoline product may contain about 150 compounds. The exact compositions of gasolines vary from company to company and from season to season.…”

Section: Background Generalmentioning

confidence: 99%

“…Data composed from a variety of gasoline hydrocarbon blends result in a typical gasoline formulation of approximately 62% alkanes, 7% alkenes, and 31% aromatics. [2] Various types of gasolines are formulated to achieve specific physical characteristics. In unleaded gasoline, MtBE is an oxygenating compound that is added to gasoline to increase the octane rating and to reduce emissions of carbon monoxide and other pollutants.…”

Section: Background Generalmentioning

confidence: 99%

HETA-94-0220-2526, Exxon Company USA, Houston, Texas.

Cook¹,

Kovein²

1995

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This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved. applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports ii PREFACEThe Hazard Evaluations and Technical Assistance Branch of NIOSH conducts field investigations of possible health hazards in the workplace. These investigations are conducted under the authority of Section 20(a)(6) of the Occupational Safety and Health Act of 1970, 29 U.S.C. 669(a)(6) which authorizes the Secretary of Health and Human Services, following a written request from any employer and authorized representative of employees, to determine whether any substance normally found in the place of employment has potentially toxic effects in such concentrations as used or found.The Hazard Evaluations and Technical Assistance Branch also provides, upon request, medical, nursing, and industrial hygiene technical and consultative assistance (TA) to federal, state, and local agencies; labor; industry; and other groups or individuals to control occupational health hazards and to prevent related trauma and disease. Mention of company names or products does not constitute endorsement by the National Institute for Occupational Safety and Health. ACKNOWLEDGMENTS AND AVAILABILITY OF REPORT SUMMARYDuring November 30 through December 2, 1994, the National Institute for Occupational Safety and Health (NIOSH) conducted a health hazard evaluation (HHE) at two Exxon service stations located in the greater Newark, New Jersey area. NIOSH investigators performed environmental monitoring to assess service station attendants' exposures to oxygenated gasoline that contained methyl tert-butyl ether (MtBE), which is an oxygenating compound blended with unleaded gasoline to help reduce vehicle emissions. Environmental measurements were made using two methods: (1) conventional air sampling (NIOSH Method 1615) and (2) video exposure monitoring with the use of real-time instrumentation.Laboratory analysis of 21 personal breathing-zo...

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Health Studies Indicate MTBE Is Safe Gasoline Additive

Cited by 9 publications

References 0 publications

Body Burden Measurements and Models to Assess Inhalation Exposure to Methyl Tertiary Butyl Ether (MTBE)

Body Burden Measurements and Models to Assess Inhalation Exposure to Methyl Tertiary Butyl Ether (MTBE)

Interaction between Titles 2 and 3 of the Clean Air Act as amended, 1990

HETA-94-0220-2526, Exxon Company USA, Houston, Texas.

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