NIOSH logo and tagline

N-Ethylmorpholine

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

CAS number: 100–74–3

NIOSH REL: 5 ppm (23 mg/m3) TWA [skin]

Current OSHA PEL: 20 ppm (94 mg/m3) TWA [skin]

1989 OSHA PEL: 5 ppm (23 mg/m3) TWA [skin]

1993-1994 ACGIH TLV: 5 ppm (24 mg/m3) TWA [skin]

Description of Substance: Colorless liquid with an ammonia-like odor.

LEL:. . Unknown

Original (SCP) IDLH: 2,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement that 1 of 6 rats died following a 4-hour exposure to 2,000 ppm [Smyth et al. 1954 cited by ACGIH 1971].

Short-term exposure guidelines: None developed

ACUTE TOXICITY DATA

Lethal concentration data:

Species Reference LC50(ppm) LCLo(ppm) Time Adjusted 0.5-hrLC (CF) Derivedvalue
Rat Smyth et al. 1954 LC17: 2,000 —– 4 hr 4,000 ppm (2.0) 400 ppm

 

Lethal dose data:

Species Reference Route LD50(mg/kg) LDLo(mg/kg) Adjusted LD Derived value
RatMouse Smyth et al. 1954Timofievskaya 1979 oraloral 1,7801,200 ———- 2,601 ppm1,754 ppm 260 ppm175 ppm

 

Human data: Exposures to 100 ppm for 2.5 minutes have resulted in olfactory fatigue and irritation of the eyes, nose, and throat; irritation was slight after 25 minutes at 50 ppm and absent at 25 ppm [Smyth 1964]. Corneal edema has been noted in workers exposed to concentrations greater than 40 ppm for several hours [Dernehl 1966]. In another study, workers exposed to concentrations as high as 11 ppm but averaging about 3 to 4 ppm complained of drowsiness, optical halos, and foggy vision [Woewicki 1968].

 

REFERENCES:

1. ACGIH [1971]. N-Ethylmorpholine. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 113.

2. Dernehl CU [1966]. Health hazards associated with polyurethane foams. J Occup Med 8:59-62.

3. Smyth JF Jr [1964]. Personal communication to ACGIH TLV Committee (November 24, 1964). [From ACGIH [1991]. N-Ethyl morpholine. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 638-639.]

4. Smyth HF Jr, Carpenter CP, Weil CS, Pozzani UC [1954]. Range-finding toxicity data: list V. AMA Arch Ind Hyg Occup Med 10:61-68.

5. Timofievskaya LA [1979]. Comparative evaluation of the toxicity of piperazine and N-methyl piperazine. Toksikol Nov Prom Khim Vesh 15:116-123 (in Russian).

6. Woewicki A [1968]. Personal communication to ACGIH TLV Committee. [From ACGIH [1991]. N-Ethyl morpholine. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 638-639.]