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Chemical Sampling Information (CSI)
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General Description

Synonyms: Diethyleneimide oxide; Diethylene imidoxide; Diethylene oximide; Tetrahydro-1,4-oxazine; Tetrahydro-p-oxazine

OSHA IMIS Code Number: 1797

Chemical Abstracts Service (CAS) Registry Number: 110-91-8

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: QD6475000

Department of Transportation Regulation Number (49 CFR 172.101) and Guide: 2054 132

NIOSH Pocket Guide to Chemical Hazards, Morpholine: chemical description, physical properties, potentially hazardous incompatibilities, and more

Exposure Limits

OSHA Permissible Exposure Limit (PEL):

General Industry: 29 CFR 1910.1000 Table Z-1 -- 20 ppm, 70 mg/m3 TWA; Skin

Construction Industry: 29 CFR 1926.55 Appendix A -- 20 ppm, 70 mg/m3 TWA; Skin

Maritime: 29 CFR 1915.1000 Table Z-Shipyards -- 20 ppm, 70 mg/m3 TWA; Skin

American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 20 ppm, 71 mg/m3 TWA; Skin; Appendix A4 - Not Classifiable as a Human Carcinogen

National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): 20 ppm, 70 mg/m3 TWA; 30 ppm, 105 mg/m3 STEL; Skin

Health Factors

Carcinogenic Classification:

International Agency for Research on Cancer (IARC) carcinogenic classification: Group 3, not classifiable as to its carcinogenicity to humans [18 KB PDF, 4 pages]

NIOSH Immediately Dangerous To Life or Health Concentration (IDLH): 1,400 ppm

Potential Symptoms: Irritation of eyes, skin, nose, respiratory system; visual disturbance cough, shortness of breath, labored breathing, pulmonary edema (may be delayed); in animals: liver, kidney damage; SKIN ABS.: Redness, pain, burns, blisters; INGES. ACUTE: Abdominal pain, burning sensation; nausea, vomiting, diarrhea; shock or collapse.

Health Effects: Irritation–Eye, Nose, Throat, Skin---severe (HE14) Cumulative liver and kidney damage (HE3)

Affected Organs: Eyes, skin, respiratory system, liver, kidneys


  1. Explosive vapor/air mixtures of morpholine may be formed above 35°C. NIOSH's IDLH for morpholine is 10% of its lower explosive limit.
  2. Morpholine is listed among FDA's "secondary direct food additives permitted in food for human consumption" (except in milk and milk products) as a boiler water additive not to exceed 10 ppm in steam (21 CFR 173.310).
  3. In animal studies, morpholine was excreted largely unchanged in the urine, showing major metabolite formation (~20% N-methylmorpholine-N-oxide) only in guinea pigs. Plasma elimination half-lives ranged from 2 hours in hamsters to 5 hours in guinea pigs.

Date Last Revised: 04/17/2007

Literature Basis:

  • NIOSH Pocket Guide to Chemical Hazards: Morpholine.
  • International Chemical Safety Cards (WHO/IPCS/ILO): Morpholine.
  • [No authors listed]: Morpholine [18 KB PDF, 4 pages]. IARC Monogr. Eval. Carcinog. Risks Hum. 47: 199-213, 1989.
  • Pohanish, R.P. (editor): Morpholine. In, Sittig’s Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 2. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 1639-1641.
Monitoring Methods used by OSHA

Laboratory Sampling/Analytical Method:

  • sampling media: XAD-7 tube (coated with 10% phosphoric acid) (80/40 mg sections, 20/40 mesh)
    analytical solvent: 1 mL 20:80 water:methanol, shake 0.5 hour, then 0.5 mL removed and added to 0.5 mL 20:80 1 N NaOH:methanol
    maximum volume: 10 Liters   
    maximum flow rate: 0.1 L/min
    current analytical method: Gas Chromatography; GC/FID
    method reference: OSHA Manual of Analytical Methods (OSHA PV2123)
    method classification: Partially Validated

On-Site Sampling Techniques/Methods:

  • device: Instrumentation
    manufacturer: Infrared Spectrophotometer
    model/type: MIRAN 1A & 1B
    sampling information: 0.7 ppm @ 9.1 μm
    method reference: on-site air secondary (manufacturer)

  • device: Instrumentation
    manufacturer: Infrared Spectrophotometer
    model/type: MIRAN 103
    sampling information: 0-100 ppm @ 9.0 μm
    method reference: on-site air secondary (manufacturer)

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