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2D Structure
Also known as: Tert-butyl methyl ether, 1634-04-4, Mtbe, 2-methoxy-2-methylpropane, Methyl t-butyl ether, Propane, 2-methoxy-2-methyl-
Molecular Formula
C5H12O
Molecular Weight
88.15  g/mol
InChI Key
BZLVMXJERCGZMT-UHFFFAOYSA-N
FDA UNII
29I4YB3S89

Methyl tert-butyl ether is used as a gasoline additive. Exposure may occur by breathing air contaminated with auto exhaust or gasoline fumes while refueling autos. Respiratory irritation, dizziness, and disorientation have been reported by some motorists and occupationally exposed workers. Acute (short- term) exposure of humans to methyl tert-butyl ether also has occurred during its use as a medical treatment to dissolve cholesterol gallstones. Chronic (long-term) inhalation exposure to methyl tert-butyl ether has resulted in central nervous system (CNS) effects, respiratory irritation, liver and kidney effects, and decreased body weight gain in animals. Developmental effects have been reported in rats and mice exposed via inhalation. EPA has not classified methyltert-butyl ether with respect to potential carcinogenicity.
1 2D Structure

2D Structure

2 Identification
2.1 Computed Descriptors
2.1.1 IUPAC Name
2-methoxy-2-methylpropane
2.1.2 InChI
InChI=1S/C5H12O/c1-5(2,3)6-4/h1-4H3
2.1.3 InChI Key
BZLVMXJERCGZMT-UHFFFAOYSA-N
2.1.4 Canonical SMILES
CC(C)(C)OC
2.2 Other Identifiers
2.2.1 UNII
29I4YB3S89
2.3 Synonyms
2.3.1 MeSH Synonyms

1. Methyl T-butyl Ether

2. Mtbe

3. Tert-butyl Methyl Ether

2.3.2 Depositor-Supplied Synonyms

1. Tert-butyl Methyl Ether

2. 1634-04-4

3. Mtbe

4. 2-methoxy-2-methylpropane

5. Methyl T-butyl Ether

6. Propane, 2-methoxy-2-methyl-

7. T-butyl Methyl Ether

8. Methyl-tert-butyl Ether

9. Methyl-t-butyl Ether

10. 2-methyl-2-methoxypropane

11. Methyl Tertiary-butyl Ether

12. Tert-butylmethylether

13. Ether, Tert-butyl Methyl

14. Methyl 1,1-dimethylethyl Ether

15. Tert-butylmethyl Ether

16. Tert-c4h9och3

17. 1,1-dimethylethyl Methyl Ether

18. Methyl-tert-butylether

19. 2-methoxy-2-methyl-propane

20. Chebi:27642

21. Methyl-tert-butyl-ether

22. Methyl Tertiary Butyl Ether

23. 29i4yb3s89

24. Mfcd00008812

25. Tbme

26. Tert-buome

27. Methyl-t-butylether

28. T-butylmethyl Ether

29. Methyltertbutyl Ether

30. Tertbutylmethyl Ether

31. Ccris 7596

32. Hsdb 5847

33. Methyl Tert Butyl Ether

34. Einecs 216-653-1

35. Un2398

36. Tert-butyl Methyl Ether, For Hplc, >=99.8% (gc)

37. Brn 1730942

38. Driveron

39. Unii-29i4yb3s89

40. Meotbu

41. Tbuome

42. T-butylmethylether

43. Methylterbutyloxide

44. Tert-butyl Methyl Ether, Hplc Plus, For Hplc, Gc, And Residue Analysis, 99.9%

45. Methyltertbutylether

46. Tertbutylmethylether

47. Methyl T-butylether

48. Methylt-butyl Ether

49. T-buome

50. T-butyl Methylether

51. T-butyl-methylether

52. Tert-butylmethyether

53. Mtbe Acs Grade

54. Tert.butylmethylether

55. T-butyl Methyi Ether

56. T-butyl-methyl Ether

57. T-butyl-methyl-ether

58. Methyl Tert-butylether

59. Methyl Tertbutyl Ether

60. Methyl-tert.butylether

61. Methyl-tertbutyl Ether

62. Methyl-tertbutyl-ether

63. Methyltert-butyl Ether

64. Tert -butylmethylether

65. Tert Butylmethyl Ether

66. Tert-butyl-methylether

67. Tert. Butylmethylether

68. Tert.-butylmethylether

69. Tert.butyl-methylether

70. Tert.butylmethyl Ether

71. Tertbutyl Methyl Ether

72. Tertbutyl(methyl)ether

73. Tert-butyl Methylether

74. Methy Tert-butyl Ether

75. Methyl Ter-butyl Ether

76. Metyl Tert-butyl Ether

77. Ter-butyl Methyl Ether

78. Tert-buty Methyl Ether

79. Tert-buyl Methyl Ether

80. Methyl Tert.-butylether

81. Methyl Tert.butyl Ether

82. Methyl-tert Butyl Ether

83. Methyl-tert. Butylether

84. Methyl-tert.-butylether

85. Methyl-tert.butyl Ether

86. Mtbe-hp

87. Tert-butyl-methyl Ether

88. Tert-butyl-methyl-ether

89. Tert. Butyl-methylether

90. Tert.-butyl Methylether

91. Tert.-butyl-methylether

92. Tert.-butylmethyl Ether

93. Tert.butyl Methyl Ether

94. Tert Butyl Methyl Ether

95. Tert-butoxymethane

96. Methyl Tert.-butyl Ether

97. Methyl-tert. Butyl Ether

98. Tert. Butyl-methyl-ether

99. Tert.-butyl Methyl Ether

100. Tert.-butyl-methyl Ether

101. Tert.-butyl-methyl-ether

102. Dsstox_cid_833

103. Methyl-tertiarybutyl Ether

104. Tert. Butyl Methyl Ether

105. Tertiary Butylmethyl Ether

106. Methyl Tert.- Butyl Ether

107. Epitope Id:122671

108. Tertiary-butyl Methyl Ether

109. Ec 216-653-1

110. Tertiary Butyl Methyl Ether

111. Dsstox_rid_75817

112. Dsstox_gsid_20833

113. 4-01-00-01615 (beilstein Handbook Reference)

114. (ch3)3coch3

115. Methyl-tert-butyl Ether (mtbe)

116. Chembl1452799

117. Dtxsid3020833

118. (methyl)(tert-butyl)ether

119. Zinc967772

120. Amy11032

121. Tert-butylmethyl Ether, Hplc Grade

122. T-butyl Methyl Ether [inci]

123. Tox21_201184

124. Tert-butyl Methyl Ether, Hplc Grade

125. Methyl Tert-butyl Ether [mi]

126. Akos000121105

127. Methyl Tert-butyl Ether [iarc]

128. Tert-butyl Methyl Ether, Lr, >=99%

129. Un 2398

130. Tert-butylmethyl Ether [usp-rs]

131. Ncgc00091717-01

132. Ncgc00091717-02

133. Ncgc00258736-01

134. Tert-butyl Methyl Ether, P.a., 99.5%

135. Cas-1634-04-4

136. Methyl Tertiary Butyl Ether - High Purity

137. Tert-butyl Methyl Ether, Ar, >=99.5%

138. Db-030412

139. B0991

140. Tert-butyl Methyl Ether, Analytical Standard

141. Tert-butyl Methyl Ether, Anhydrous, 99.8%

142. Tert-butyl Methyl Ether, Pra Grade, >=99%

143. Tert-butyl Methyl Ether, Reagent Grade, 98%

144. Tert-butyl Methyl Ether, For Hplc, >=99.8%

145. Tert-butyl Methyl Ether, For Hplc, >=99.9%

146. Tert-butyl Methyl Ether, Reagent Grade, >=98%

147. Methyl-tert-butylether 100 Microg/ml In Methanol

148. Q412346

149. Tert-butyl Methyl Ether, Acs Reagent, >=99.0%

150. Tert-butylmethyl Ether 100 Microg/ml In Methanol

151. J-509782

152. Methyl Tert-butyl Ether 2000 Microg/ml In Methanol

153. Tert-butyl Methyl Ether, Puriss. P.a., >=99% (gc)

154. Methyl Tert-butyl Ether [un2398] [flammable Liquid]

155. Mtbe Acs Grade Trace Metal Grade, Stainless Steel Drum

156. Tert-butyl Methyl Ether, Hplc Grade, For Hplc, 99.8%

157. Tert-butyl Methyl Ether, Puriss. P.a., >=99.5% (gc)

158. Tert-butyl Methyl Ether, Saj Special Grade, >=99.0%

159. Methyl Tert-butyl Ether (mtbe) 1000 Microg/ml In Methanol

160. Tert-butyl Methyl Ether, Pharmaceutical Secondary Standard; Certified Reference Material

161. Tert-butyl Methyl Ether, United States Pharmacopeia (usp) Reference Standard

2.4 Create Date
2005-03-27
3 Chemical and Physical Properties
Molecular Weight 88.15 g/mol
Molecular Formula C5H12O
XLogP30.9
Hydrogen Bond Donor Count0
Hydrogen Bond Acceptor Count1
Rotatable Bond Count1
Exact Mass88.088815002 g/mol
Monoisotopic Mass88.088815002 g/mol
Topological Polar Surface Area9.2 Ų
Heavy Atom Count6
Formal Charge0
Complexity33.7
Isotope Atom Count0
Defined Atom Stereocenter Count0
Undefined Atom Stereocenter Count0
Defined Bond Stereocenter Count0
Undefined Bond Stereocenter Count0
Covalently Bonded Unit Count1
4 Drug and Medication Information
4.1 Therapeutic Uses

Methyl-tertiary butyl ether (MTBE) /is/ a ... US Food and Drug Administration approved gallstone treatment ... .

PMID:22407988 Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4378906 Kozlosky J et al; J Appl Toxicol 33 (8): 820-7 (2013)


... Patients (aged 37-75 yr) with a history of biliary colic and radiolucent gallstones ... were given continuous methyl tert-butyl ether (MTBE I) infusion through a catheter ... .

Ponchon T et al; Lancet 2 (July 30): 276-277 (1988)


5 Pharmacology and Biochemistry
5.1 MeSH Pharmacological Classification

Air Pollutants

Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or materials. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS. (See all compounds classified as Air Pollutants.)


Carcinogens

Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included. (See all compounds classified as Carcinogens.)


5.2 Absorption, Distribution and Excretion

... 10 healthy male volunteers /were exposed/ to methyl tert-butyl ether (MTBE) vapor at 5, 25 and 50 ppm for 2 hr during light physical exercise. Uptake and disposition were studied by measuring MTBE and tert-butyl alcohol (TBA) in inhaled and exhaled air, blood and urine. Low uptake, high post-exposure exhalation, and low blood clearance indicate slow metabolism of MTBE relative to many other solvents. A low recovery of TBA in urine (below 1% of uptake) indicates further metabolism of TBA. The concentration of MTBE and TBA in blood was proportional to exposure level suggesting linear kinetics up to 50 ppm. The half life of 7-10 hr in blood and urine indicates that TBA would be more suitable than the parent compound as a biomarker for MTBE exposure. Subjective ratings (discomfort, irritative symptoms, CNS effects) and eye (redness, tear film break-up time, conjunctival damage, blinking frequency) and nose (peak expiratory flow, acoustic rhinometry, inflammatory markers in nasal lavage) measurements indicated no or minimal effects of MTBE.

PMID:8597131 Johanson G et al; Toxicol Lett 82-83: 713-8 (1995)


After inhalation exposure methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are rapidly taken up by both rats and humans; after termination of exposure, clearance by exhalation and biotransformation to urinary metabolites is rapid in rats. In humans, clearance by exhalation is slower in comparison to rats. Biotransformation of MTBE and ETBE is both qualitatively and quantitatively similar in humans and rats after inhalation exposure under identical conditions. The extent of biotransformation of TAME is also quantitatively similar in rats and humans; the metabolic pathways, however, are different. ...

PMID:11684356 Dekant W et al; Toxicol Lett 124 (1-3): 37-45


Groups of male and female rats /strain not specified/ received a single 6 hr exposure to methyl tert-butyl ether (MTBE) vapor in nose-only inhalation chambers at targeted MTBE concentrations of 400 and 8000 ppm and daily repeat 6 hr exposures for 15 days at a targeted MTBE concentration of 400 ppm. Four rats/sex/group were then euthanized and examined. Steady-state plasma concentrations were reached at approximately 4 to 6 hr for MTBE and roughly 6.5 hr for TBA /tert-butyl alcohol/, the principal metabolite of MTBE. MTBE-metabolizing enzymes were saturated during high-concentration exposure. The elimination half-life (t1/2) of MTBE was approximately the same after single low- and high-concentration exposures (0.52 and 0.63 hr, respectively). After the repeat exposures, the MTBE t1/2 was slightly shorter (0.48 and 0.51, respectively). The TBA t1/2 ranged from 2.8 to 3.4 hr after the low- and high-concentration single exposures. After the repeat exposure regimen, the TBA t1/2 was significantly lower (1.8 and 1.5 hr in the male and female rats, respectively). There was a slight, but statistically significant, sex difference in the pharmacokinetics of MTBE (e.g., plasma clearance was faster in females), but no sex differences in the elimination kinetics of TBA were observed.

U.S. Environmental Protection Agency's Integrated Risk Information System (IRIS) on Methyl tert-butyl ether (MTBE) (1634-04-4). Available from, as of September 29, 2010: https://www.epa.gov/iris/subst/index.html


In a group of 2 healthy men and 2 healthy women experimentally exposed to 1.7 ppm methyl tert-butyl ether (MTBE) for 1 hr, mean blood levels of MTBE rose steeply from a level of 0.83 ug/L preexposure to 17.14 ug/L at the end of the 1-hr exposure, followed by a decline to an average level of 9.74 ug/L at 40 minutes postexposure and 6.32 ug/L at 60 minutes postexposure.

U.S. Dept Health & Human Services/Agency for Toxic Substances & Disease Registry; Toxicological Profile for Number 98: Methyl tert-butyl ether p.89 (August 1996). Available from, as of October 8, 2010: https://www.atsdr.cdc.gov/toxprofiles/index.asp


For more Absorption, Distribution and Excretion (Complete) data for Methyl t-butyl ether (9 total), please visit the HSDB record page.


5.3 Metabolism/Metabolites

The biotransformation of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) was studied in humans and in rats after inhalation of 4 and 40 ppm of MTBE, ETBE, and TAME, respectively, for 4 hours, and the biotransformation of MTBE and TAME was studied after ingestion exposure in humans to 5 and 15 mg in water. tert-Butyl alcohol (TBA), a TBA conjugate, 2-methyl-1,2-propanediol, and 2-hydroxyisobutyrate were found to be metabolites of MTBE and ETBE. tert-Amyl alcohol (TAA), free and glucuronidated 2-methyl-2,3-butanediol (a glucuronide of TAA), 2-hydroxy-2-methyl butyrate, and 3-hydroxy-3-methyl butyrate were found to be metabolites of TAME. After inhalation, MTBE, ETBE, and TAME were rapidly taken up by both rats and humans; after termination of exposure, clearance from blood of the ethers by exhalation and biotransformation to urinary metabolites occurred with half-times of less than 7 hours in rats and humans. Biotransformation of MTBE and ETBE was similar in humans and rats after inhalation exposure. 2-Hydroxyisobutyrate was recovered as a major product in urine. All metabolites of MTBE and ETBE excreted with urine were eliminated with half-times of less than 20 hours. Biotransformation of TAME was qualitatively similar in rats and humans, but the metabolic pathways were different. In humans, 2-methyl-2,3-butanediol, 2-hydroxy-2-methyl butyrate, and 3-hydroxy-3methyl butyrate were recovered as major urinary products. In rats, however, 2-methyl-2,3-butanediol and its glucuronide were major TAME metabolites recovered in urine. After ingestion of MTBE and TAME, both compounds were rapidly absorbed from the gastrointestinal tract. Hepatic first-pass metabolism of these ethers was not observed, and a significant part of the administered dose was transferred into blood and cleared by exhalation. Metabolic pathways for MTBE and TAME and kinetics of excretion were identical after ingestion and inhalation exposures. ...

PMID:11504147 Dekant W et al; Res Rep Health Eff Inst (102): 29-71 (2001)


Methyl tert-butyl ether (MTBE) is ... metabolized to tert-butanol in rats. The metabolism of (14)C-MTBE has been studied in Fischer 344 rats exposed by the inhalation, oral, dermal, and intravenous routes. Respiratory and urinary metabolites were generally similar following exposure of Fischer 344 rats by all routes, indicating pathways are not route-dependent. After exposure by all routes, most of the exhaled radioactivity was due to unchanged MTBE and tert-butanol, with MTBE predominating. Only a small amount of (14)C-carbon dioxide was detected. MTBE and tert-butanol were generally not found in the urine, but four urinary metabolites were isolated, with two identified as alpha-hydroxyisobutyric acid and 2-methyl-1,2-propanediol. The two other metabolites remained unidentified. After inhalation and oral exposure, there was a larger fraction of exhaled tert-butanol in low dose rats than in high dose rats. In inhalation experiments, rats were exposed to (14)C-MTBE at 400 or 8000 ppm for 6 hr or to 400 ppm unlabeled MTBE for 6 hr per day for 14 days, then to 400 ppm (14)C-MTBE on day 15. tert-Butanol accounted for 25 and 30% of the recovered radioactivity in expired air at 3 hr after the single and repeated low exposure concentration, respectively. Exposure to the higher concentration for 6 hr resulted in a lower fraction recovered (7-10%) as a result of to tert-butanol. At 3-6 hr after exposure, tert-butanol represented 72-80% of the radioactivity at the low dose in the single and repeated exposure experiments and 43-54% at the high dose. Results of dosing Fischer 344 rats with (14)C-MTBE intravenously were similar to those obtained by the inhalation, oral and dermal routes. In Charles River CD (Sprague-Dawley) rats injected with a single intraperitoneal dose of 232 mg/kg (14)C-MTBE, blood, tissue, expired air, urine, and feces were sampled at various times up to 48 hr. At 6 hr about 92% of the radioactive dose was eliminated in expired air, 99.1% of which was unchanged MTBE. An average of 7.38% of the administered dose was expired as radiolabeled carbon dioxide. Analysis of the urine revealed that radiolabeled formic acid accounted for 96.6% of the urinary radioactivity. The remaining radioactivity in the urine was assumed to be radiolabeled methanol and formaldehyde. Methanol and formic acid were also detected in plasma, kidney, and liver. No tert-butanol was found in the urine. The metabolism of MTBE to formaldehyde was studied using liver microsomes from control and phenobarbital-pretreated rats (strain not specified). Phenobarbital pretreatment approximately doubled the formation of formaldehyde from MTBE. Further metabolism of formaldehyde yields methanol and/or formic acid; the probable enzymes and cofactors are alcohol dehydrogenase and NADH for the formation of methanol and aldehyde dehydrogenase and NAD for the formation of formic acid.

Mehlman MA, Patty's Toxicology CD-ROM (2005). NY, NY: John Wiley & Sons; Ethers. Online Posting Date: April 16, 2001


Exposure to methyl tertiary-butyl ether (MTBE) previously /has/ been shown to alter various muscle, kidney, and liver metabolic activities. In the present study, the metabolism of MTBE by liver microsomes from acetone- or phenobarbital-treated Sprague-Dawley rats was studied at concn of up to 5 mM MTBE. Equimolar amounts of tertiary- butanol, as measured by head-space gas chromatography, and formaldehyde were formed. The Vmax for the demethylation increased by 4 fold and 5.5 fold after acetone and phenobarbital treatments, respectively. The apparent Km value of 0.70 mM using control microsomes was decreased slightly after acetone treatment, but was increased by 2 fold after phenobarbital treatment. The metabolism of MTBE (1 mM) was inhibited by 35% by monoclonal antibodies against p450IIE1, the acetone/ethanol inducible form of cytochrome p450, suggesting a partial contribution by this isozyme. A single 18 hr pretreatment of rats with 1 or 5 mL/kg MTBE (ip) resulted in a 50 fold induction of liver microsomal pentoxyresorufin dealkylase activity but no change in N-nitrosodimethylamine demethylase activity. These trends in activity agreed with immunoblot analysis which showed an elevation in p450IIB1 but no change in p450IIE1 level.

PMID:2350236 Brady JF et al; Arch Toxicol 64 (2): 157-60 (1990)


/The/ human liver is active in the oxidative metabolism of ETBE and TAME. A large interindividual variation in metabolizing these gasoline ethers was observed in 15 human liver microsomal samples. The microsomal activities in metabolizing methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) were highly correlated among each other (r, 0.91-0.96), suggesting that these ethers are metabolized by the same enzyme(s). Correlation analysis of the ether-metabolizing activities with individual CYP enzyme activities in the liver microsomes showed that the highest degree of correlation was with human CYP2A6 (r, 0.90-0.95) ... CYP2A6 displayed the highest turnover number in metabolizing gasoline ethers among a battery of human CYP enzymes expressed in human B-lymphoblastoid cells. Kinetic studies on MTBE metabolism with three human liver microsomes exhibited apparent Km values that ranged from 28 to 89 uM and the V(max) values from 215 to 783 pmol/min/mg, with similar catalytic efficiency values (7.7 to 8.8 uL/min/mg protein). Metabolism of MTBE, ETBE, and TAME by human liver microsomes was inhibited by coumarin, a known substrate of human CYP2A6, in a concentration-dependent manner. Monoclonal antibody against human CYP2A6 caused a significant inhibition (75% to 95%) of the metabolism of MTBE, ETBE, and TAME in human liver microsomes. ...

PMID:10502501 Hong JY et al; Toxicol Appl Pharmacol 160 (1): 43-48 (1999)


For more Metabolism/Metabolites (Complete) data for Methyl t-butyl ether (9 total), please visit the HSDB record page.


Tert-butyl methyl ether has known human metabolites that include tert-butanol.

S73 | METXBIODB | Metabolite Reaction Database from BioTransformer | DOI:10.5281/zenodo.4056560


5.4 Biological Half-Life

MTBE is rapidly metabolized and excreted with a half-life of approximately 30 min /Rats/.

Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. V5 889


Groups of male and female rats /strain not specified/ received a single 6 hr exposure to methyl tert-butyl ether (MTBE) vapor in nose-only inhalation chambers at targeted MTBE concentrations of 400 and 8000 ppm and daily repeat 6 hr exposures for 15 days at a targeted MTBE concentration of 400 ppm ... The elimination half-life (t1/2) of MTBE was approximately the same after single low- and high-concentration exposures (0.52 and 0.63 hr, respectively). After the repeat exposures, the MTBE t1/2 was slightly shorter (0.48 and 0.51, respectively). The TBA /tert-butyl alcohol/ t1/2 ranged from 2.8 to 3.4 hr after the low- and high-concentration single exposures. After the repeat exposure regimen, the TBA t1/2 was significantly lower (1.8 and 1.5 hr in the male and female rats, respectively).

U.S. Environmental Protection Agency's Integrated Risk Information System (IRIS) on Methyl tert-butyl ether (MTBE) (1634-04-4). Available from, as of September 29, 2010: https://www.epa.gov/iris/subst/index.html


Healthy male volunteers were exposed via inhalation to gasoline oxygenates methyl tert-butyl ether (MTBE)... The half-times for MTBE in blood were about 1.7 and 3.8 hr. In urine, /MTBE/ showed half-times of about 4 hr ... .

PMID:17668360 Vainiotalo S et al; J Occup Environ Hyg 4 (10): 739-50 (2007)


MTBE was rapidly cleared from blood with a half-life of 2.6 +/- 0.9 hr in humans and 0.5 +/- 0.2 hr in rats.

PMID:10496672 Amberg A et al; Toxicol Sci 51 (1): 1-8 (1999)


The biotransformation of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) was studied in humans and in rats after inhalation of 4 and 40 ppm of MTBE, ETBE, and TAME, respectively, for 4 hours, and the biotransformation of MTBE and TAME was studied after ingestion exposure in humans to 5 and 15 mg in water. tert-Butyl alcohol (TBA), a TBA conjugate, 2-methyl-1,2-propanediol, and 2-hydroxyisobutyrate were found to be metabolites of MTBE and ETBE. ... After termination of exposure, clearance from blood of the ethers by exhalation and biotransformation to urinary metabolites occurred with half-times of less than 7 hours in rats and humans. ... All metabolites of MTBE and ETBE excreted with urine were eliminated with half-times of less than 20 hours. ...

PMID:11504147 Dekant W et al; Res Rep Health Eff Inst (102): 29-71 (2001)