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1,1-Dichloroethane (CAS number: 75–34–3)

May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 75–34–3

NIOSH REL: 100 ppm (400 mg/m3) TWA

Current OSHA PEL: 100 ppm (400 mg/m3) TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 100 ppm (400 mg/m3) TWA

Description of Substance: Colorless, oily liquid with a chloroform-like odor.

LEL:. . 5.4% (10% LEL, 5,400 ppm)

Original (SCP) IDLH: 4,000 ppm

Basis for original (SCP) IDLH: Patty [1963] reported that rats survived 8-hour exposures to 4,000 ppm, but died at 16,000 ppm [Smyth 1956]. However, 16,000 ppm has not been chosen as the IDLH because Kirk-Othmer [1964] indicated that 1,1-dichloroethane causes narcosis. For this draft technical standard, 4,000 ppm is chosen as the IDLH.

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50(ppm) LCLo(ppm) Time Adjusted 0.5-hrLC (CF) Derivedvalue


Carpenter et al. 1949Mueller 1925

Smyth 1956





4 hr2 hr

8 hr

32,000 ppm (2.0)27,680 ppm (1.6)

40,000 ppm (2.5)

3,200 ppm2,768 ppm

4,000 ppm


Human data: None relevant for use in determining the revised IDLH.



1. Carpenter CP, Smyth HF Jr, Pozzani UC [1949]. The assay of acute vapor toxicity, and the grading and interpretation of results on 96 chemical compounds. J Ind Hyg Toxicol 31:343-346.

2. Kirk-Othmer [1964]. Encyclopedia of chemical technology. 2nd ed. New York, NY: John Wiley & Sons, Inc. 5:92-98.

3. Mueller J [1925]. Comparative investigations on the anesthetic and toxic effects of some halogenated hydrocarbons. Arch Exp Pathol Pharmakol 109:276-294 (in German). [From ACGIH [1991]. 1,1-Dichloroethane. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 425-428.]

4. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., pp. 1279-1280.

5. Smyth HF Jr [1956]. Improved communication: hygienic standards for daily inhalation. Am Ind Hyg Assoc Q 17(2):129-185.