N­Ethylmorpholine

IDLH Documentation

CAS number: 100­74­3

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 ammonia­like 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 4­hour 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-hr

LC (CF)
Derived

value
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
Rat

Mouse
Smyth et al. 1954

Timofievskaya 1979
oral

oral
1,780

1,200
-----

-----
2,601 ppm

1,754 ppm
260 ppm

175 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 ppm

Basis for revised IDLH: The revised IDLH for N­ethylmorpholine 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]. N­Ethylmorpholine. 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 8:59­62.

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

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

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

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