An official website of the United States government
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].
| Revised IDLH: 100 ppmBasis for revised IDLH: The revised IDLH for N-ethylmorpholine is 100 ppm based on acute inhalation toxicity data in humans [Dernehl 1966; Smyth 1964]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 100 ppm. |
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.]