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Toxicity study of dimethylethoxysilane (DMSES), the waterproofing agent for the Orbiter heat protective systemDMES, a volatile liquid, is used by NASA to waterproof the Orbiter thermal protective system. During waterproofing operations at the Oribter Processing Facility at KSC, workers could be exposed to DMES vapor. To assess the toxicity of DMES, acute and subchronic (2-week and 13-week) inhalation studies were conducted with rats. Studies were also conducted to assess the potential of DMES. Inhalation exposure concentrations ranged from 40 ppm to 4000 ppm. No mortality was observed during the studies. Exposures to 2100 ppm produced narcosis and ataxia. Post-exposure recovery from these CNS effects was rapid (less than 1 hr). These effects were concentration-dependent and relatively independent of exposure length. Exposure to 3000 ppm for 2 weeks (5 h/d, 5 d/wk) produced testicular toxicity. The 13-week study yielded similar results. Results from the genotoxicity assays (in vivo/in vitro unscheduled DNA synthesis in rat primary heptaocytes, chromosomal aberrations in rat bone marrow cells; reverse gene mutation in Salmonella typhimurium; and forward mutation in Chinese hamster culture cells) were negative. These studies indicated that DMES is mildly to moderately toxic but not a multagen.
Document ID
19940007082
Document Type
Conference Paper
Authors
Lam, Chiu-Wing (Krug Life Sciences, Inc. Houston, TX., United States)
James, John T. (NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Dodd, Darol (ManTech Environmental Technology, Inc. Upton, NY., United States)
Stuart, Bruce (ManTech Environmental Technology, Inc. Upton, NY., United States)
Rothenberg, Simon (ManTech Environmental Technology, Inc. Upton, NY., United States)
Kershaw, Mary Ann (Brookhaven National Lab. Upton, NY., United States)
Thilagar, A. (Sitek Research Labs. Rockville, MD., United States)
Date Acquired
September 6, 2013
Publication Date
February 1, 1993
Publication Information
Publication: Sixth Annual Workshop on Space Operations Applications and Research (SOAR 1992), Volume 2
Subject Category
MAN/SYSTEM TECHNOLOGY AND LIFE SUPPORT
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19940007055Analytic PrimarySixth Annual Workshop on Space Operations Applications and Research (SOAR 1992), volume 2