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Chemical Sampling Information (CSI)
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General Description

Synonyms: Methyl-t-Butyl Ether; Methyl-tert-Butyl Ether; Methoxy-2-Methyl Propane; MTBE

OSHA IMIS Code Number: B146

Chemical Abstracts Service (CAS) Registry Number: 1634-04-4

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: KN5250000

Chemical Description and Physical Properties:
molecular formula: C5H12O
molecular weight: 88.17
boiling point: 55.2°C
vapor pressure: kPa at 20°C: 27
melting point: -109°C
Exposure Limits

American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 50 ppm TWA; Appendix A3 - Confirmed Animal Carcinogen with Unknown Relevance to Humans

Health Factors

Potential Symptoms: Drowsiness, dizziness, headache, weakness, unconsciousness; redness of skin and eyes; INGES ACUTE: Nausea, vomiting, abdominal pain; chemical pneumonitis (by aspiration).

Health Effects: Irritation-Eyes, skin---mild (HE16); Nervous system disturbances (HE7); Explosive, flammable (HE18)

Affected Organs: CNS, skin, eyes

Notes:
  1. MTBE is used as a major gasoline additive (up to 15%) and experimentally for dissolving cholesterol gall stones.
  2. Metabolism of MTBE by hepatic CYP2A6 (which also metabolizes coumarin and nicotine) is strongly inhibited by the drugs, methoxsalen and tranylcypromine.
  3. Systemic exposure can occur via absorption through the skin. Most symptoms claimed for airborne MTBE exposure have not been rigorously documented, as occupational exposure is rarely to the pure compound alone. Its potent odor is recognized at 90-130 ppb.
Date Last Revised: 11/05/2003

Literature Basis:
  • (symptoms; organs affected)
    International Chemical Safety Cards (WHO/IPCS/ILO): Methyl tert-butyl ether
  • (absorption; metabolism)
    Draper, A.J., Madan, A. and Parkinson, A.: Inhibition of coumarin 7-hydroxylase activity in human liver microsomes. Arch. Biolchem. Biophys. 341(1): 47-61, 1997.
  • Prah, J.D., Blount, B., Cardinali, F.L., Ashley, D.L., Leavens, T. and Case, M.W.: The development and testing of a dermal exposure system for pharmacokinetic studies of administered and ambient water contaminants. J. Pharmacol. Toxicol. Methods 47(3): 189-195, 2002.
  • (clinical use)
    Hellstern, A., et al.: Dissolution of gallbladder stones with methyl tert-butyl ether and stone recurrence: a European survey. Dig. Dis. Sci. 43(5): 911-920, 1998.
  • (general reviews)
    Borak, J., Pastides, H., Van Ert, M., Russi, M. and Herzstein J.: Exposure to MTBE and acute human health effects: a critical literature review. Human and Ecological Risk Assessment 4(1): 177-200, 1998.
  • No Authors. Methyl tert-butyl ether [212 KB PDF, 45 page]. IARC Monogr. Eval. Carcinog. Risks Hum. 73: 339-383, 1999.
Monitoring Methods used by OSHA

Laboratory Sampling/Analytical Method:
  • sampling media: Two Charcoal Tubes in Series (Front is 400 mg/ Back is 200 mg; 20/40 mesh)
    analytical solvent: Carbon Disulfide
    maximum volume: 96 Liters
    maximum flow rate: 0.2 L/min
    current analytical method: Gas Chromatography; GC/FID
    method reference: NIOSH Manual of Analytical Methods (NIOSH 1615) [21 KB PDF, 4 pages]
    method classification: Partially Validated
    note: Store samples at reduced temperature until shipment.
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Page last updated: 02/15/2005

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