Isopropyl ether

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

CAS number: 108–20–3

NIOSH REL: 500 ppm (2,100 mg/m3) TWA

Current OSHA PEL: 500 ppm (2,100 mg/m3) TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 250 ppm (1,040 mg/m3) TWA, 310 ppm (1,300 mg/m3) STEL

Description of substance: Colorless liquid with a sharp, sweet, ether-like odor.

LEL: . . 1.4% (10% LEL, 1,400 ppm)

Original (SCP) IDLH: 10,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the UCC [1968] report that breathing the vapors in a state approaching saturation in room air killed all rats in a 10-minute exposure. [Note: Based on a vapor pressure of 119 mmHg [Patty 1963], the saturated concentration of isopropyl ether in air at 20°C is about 157,000 ppm.] Breathing 8,000 ppm was not fatal after a 4-hour exposure, but 16,000 ppm killed 6 of 6 animals exposed for the same period of time [UCC 1968].

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50




Time Adjusted 0.5-hr


Derived value
Rat Pavlova et al. 1963 38,138 ----- ? ? ?
Rabbit Pavlova et al. 1963 30,840 ----- ? ? ?
Rabbit Pavlova et al. 1963 28,486 ----- ? ? ?
Rat UCC 1968 LC100: 157,000 ----- 10 min 105,190 ppm (0.67) 10,519 ppm
Mammal UCC 1968 LC100: 16,000 ----- 4 hr 32,000 ppm (2.0) 3,200 ppm

Lethal dose data:

Species Reference Route LD50




Adjusted LD Derived value
Rabbit Machle et al. 1939 oral ----- 5,000-6,500 8,235-10,706 ppm 824-1,071 ppm
Rat UCC 1968 oral 8,470 ----- 13,951 ppm 1,395 ppm

Other animal data: It has been reported that animals survived a 4-hour exposure to 8,000 ppm [UCC 1968].

Human data: Volunteers exposed to 800 ppm for 5 minutes reported irritation of the eyes and nose [Silverman et al. 1946].

Revised IDLH: 1,400 ppm [LEL]

Basis for revised IDLH: Based on health considerations and acute inhalation toxicity data in animals [UCC 1968], a value of about 3,200 ppm would have been appropriate for isopropyl ether. However, the revised IDLH for isopropyl ether is 1,400 ppm based strictly on safety considerations (i.e., being 10% of the lower explosive limit of 1.4%).


1. Machle W, Scott EW, Treon J [1939]. The physiological response to isopropyl ether and to a mixture of isopropyl ether and gasoline. J Ind Hyg Toxicol 21:72-96.

2. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1662.

3. Pavlova LP, Lagunova VV, Imanov RM [1963]. Determination of the maximal permissible concentration of diisopropyl ether in the air of working zone. Gig Tr Prof Zabol 19(10):55-57 (in Russian).

4. Silverman L, Schulte HF, First MW [1946]. Further studies on sensory response to certain industrial solvent vapors. J Ind Hyg Toxicol 28:262-266.

5. UCC [1968]. Toxicology studies: isopropyl ether. New York, NY: Union Carbide Corporation.

Page last reviewed: December 4, 2014