Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants Volume 4 (2000) / Chapter Skim
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B8 Dichlorofluoromethane (Freon 21)
B8 Dichlorofluoromethane (Freon 21)
Pages 175-189
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BE Dichiorofluoromethane (Freon 21) Hector D
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, as did rats exposed at 1000 and 5000 ppm for 6 in/d, 5 d/w for ~ 3 w (E.T. du Pont de Nemours ~ 977~.
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du Font de Nemours, unpublished data, 1964~. Exposure to HCFC-21 at 100,000 ppm killed rats and guinea pigs in 1 h (Weigand ~ 971~.
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du Font de Nemours 1989~. Although HCFC-21 at a concentration of 2.5% in air was shown to induce arrhythmia in monkeys and to sensitize the mouse heart to epinephrine, it did not induce bradycardia in rats, in contrast to several other halocarbons (Friedman et al.
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Testing by DuPont's Haskell Laboratory found liver damage in rats exposed to HCFC-21 at 10,000 ppm, 6 in/d, 5 d/w for 2 w, and in rats exposed at 1,000 ppm, 6 in/d, 5 d/w for ~ 3 w (E.I. du Pont de Nemours 19771.
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Lethality Testing by DuPont's Haskell Laboratory found increased mortality in both mate and female rats exposed to HCFC-21 at 1000 and 5000 ppm for 6 h/d,5 d/w for 13 w (E.I. du Pont de Nemours 1977~.
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Different sections of the report gave contradictory statements as to how many animals were affected, at which doses, for which exposure durations, and whether the results were considered exposure-related and significant. A cover letter to the report stated that it had not been reviewed by TBT's quality assurance unit, because the unit had been discontinued due to Toss of personnel.
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182 I · _ x so au C: c> U)
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are calculated for the induction of each adverse effect (CNS depression, cardiac effects, and hepatotoxicity) using the guidelines established by the National TABLE S-3 Exposure Limits Set by Other Organizations Organization Exposure Limit, ppm Reference ACGTH's TLV ACGTH's TLV OSHA's PEL OSHA's STEL NIOSH's REL NIOSH's STEL NBC's 1 -h EEL NRC's 24-h EEL NRC's 90-d CEL 10 (TWA)
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, heavy spleens, enlarged lymph nodes, decreased plasma proteins, increased plasma enzyme activities, increased urine volume, increased urine fluoride, and interstitial edema of the pancreas. None of those effects is considered an adverse effect per se.
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(1977) , from DuPont's Haskell Laboratories, who, in a 90-d study on ChR-CD rats and beagle dogs exposed to HCFC-21 at 1000 or 5000 ppm for 6 in/d, 5 d/w, found extensive liver damage in rats at either test concentration, minimal morphological change in the liver of dogs exposed at 5000 ppm, and a NOAEL for liver toxicity in dogs exposed at 1000 ppm.
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Haskell Laboratory, E.I. du Pont de Nemours, Wilmington, DE.
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1992. Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants.
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