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NIOSH REL: None established; NIOSH considers methylene chloride to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].
Current OSHA PEL: 500 ppm TWA, 1,000 ppm CEILING,
2,000 ppm 5minute MAXIMUM PEAK IN ANY 2 HOURS
1989 OSHA PEL: Same as current PEL
19931994 ACGIH TLV: 50 ppm (174 mg/m3) TWA, A2
Description of substance: Colorless liquid with a chloroformlike odor.
LEL: . . . 13% (10% LEL, 13,000 ppm)
Original (SCP) IDLH: 5,000 ppm
Basis for original (SCP) IDLH: Negherbon [1959] reported that a 10minute exposure to 2,330 ppm produces vertigo in man [Lehmann et al. 1936]. However, Sax [1975] stated that at 2,300 ppm there was no feeling of dizziness during 1hour exposures. Thienes and Haley stated that no dizziness, but slight nausea, is caused by exposure to 2,300 ppm for 1 hour and that methylene chloride is not lethal at 25,000 ppm. Considering the data cited above, an IDLH of 5,000 ppm is chosen.
Shortterm exposure guidelines: None developed
ACUTE TOXICITY DATA:
Lethal concentration data:
| G. pig
Rat Rabbit Cat Mouse Dog | Clayton 1967
Fiz Akt Vesh 1975 Heppel et al. 1944 Lehmann et al. 1936 von Oettingen 1949 von Oettingen 1949 |
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Human data: Volunteers exposed at 1,000 ppm for 2 hours
had carboxyhemoglobin levels in excess of those permitted in industry
from exposure to carbon monoxide alone [Stewart et al. 1972].
A 10minute exposure at 2,330 ppm has produced vertigo
[Lehmann et al. 1936]. However, it has also been reported that
no feeling of dizziness was noted after 1 hour of exposure
to 2,300 ppm [Sax 1975]. It has been stated that no dizziness,
but slight nausea, is caused by exposure to 2,300 ppm for
1 hour and that methylene chloride is not lethal at 25,000 ppm
[Thienes and Haley].
| Revised IDLH: 2,300 ppm
Basis for revised IDLH: The revised IDLH for methylene chloride is 2,300 ppm based on acute inhalation toxicity data in humans [Sax 1975]. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for methylene chloride at any detectable concentration.] |
REFERENCES:
1. Clayton JW [1967]. Fluorocarbon toxicity and biological action. Fluor Chem Rev 1:197252.
2. Fiz Akt Vesh [1975]; 7:3536 (in Russian).
3. Heppel LA, Neal PA, Perrin TL, Orr ML, Porterfield VT [1944]. The toxicology of dichloromethane (methylene chloride). I. Studies on effects of daily inhalation. J Ind Hyg Toxicol 26(1):816.
4. Lehmann KB, SchmidtKehl L, Ruf H, Crescitelli, Dahl, Eppinghausen, Eshe, Falker, Grotefendt, Junkenita, Maier, Mergner, Pantehtsch, Schlitzer, Shoenes, Spettmann, Wirges, Bamsreiter, Benninger, Lazarus, Manasse, Kummeth, Reuss, Schwarzweller [1936]. Die 13 wichtisgsten chlorkohlenwasserstoffe der fettreihe vom standpunkt der gewerbehygiene (The 13 most important chlorinated hydrocarbons of the aliphatic series from the standpoint of occupational medicine). Arch Hyg Bakteriol 116:131200 (translated).
5. Negherbon WO [1959]. Handbook of toxicology. Vol. III. Insecticides, A compendium. WrightPatterson Air Force Base, OH: U.S. Air Force, Air Research and Development Command, Wright Air Development Center, Aero Medical Laboratory, WADC Technical Report 5516, p. 485.
6. Sax NI [1975]. Methylene chloride. In: Dangerous properties of industrial materials. 4th ed. New York, NY: Van Nostrand Reinhold Company, p. 921.
7. Stewart RD, Fisher TN, Hosko JJ, Peterson JE, Baretta ED, Dodd HC [1972]. Carboxyhemoglobin elevation after exposure to dichloromethane. Science 176:295296.
8. Thienes CH, Haley TJ [?].
9. von Oettingen WF [1949]. Studies on the relation between the
toxic action of chlorinated methanes and their physicohemical
properties. NIH Bulletin 191:185.
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