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Chemical Sampling Information (CSI)
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General Description

Synonyms: Burned lime; Burnt lime; Lime, Pebble lime; Quicklime; Unslaked lime

OSHA IMIS Code Number: 0520

Chemical Abstracts Service (CAS) Registry Number: 1305-78-8

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: EW3100000

Department of Transportation Regulation Number (49 CFR 172.101) and Guide: 1910 157

NIOSH Pocket Guide to Chemical Hazards, Calcium Oxide: 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 -- 5 mg/m3 TWA

Construction Industry: 29 CFR 1926.55 Appendix A -- 5 mg/m3 TWA

Maritime: 29 CFR 1915.1000 Table Z-Shipyards -- 5 mg/m3 TWA

American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 2 mg/m3 TWA

National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): 2 mg/m3 TWA

Health Factors

NIOSH Immediately Dangerous To Life or Health Concentration (IDLH): 25 mg/m3

Potential Symptoms: Irritation of eyes, skin, upper respiratory tract; ulcerated, perforated nasal septum; pneumonitis, pulmonary edema (may be delayed); lacrimation, spasmodic blinking; brittle nails, irritant contact dermatitis

Health Effects: Irritation-Eye, Nose, Throat, Skin---Marked (HE14)

Affected Organs: Eyes, skin, respiratory system


  1. Calcium oxide is affirmed by the FDA as a generally recognized as safe (GRAS) direct food substance (21 CFR 184.1210).
  2. Prolonged contact with wet cement, which is alkaline due to the reaction of water with calcium oxide to form calcium hydroxide, can result in full-thickness skin burns that may require surgical treatment.

Literature Basis:

  • NIOSH Pocket Guide to Chemical Hazards: Calcium Oxide.
  • International Chemical Safety Cards (WHO/IPCS/ILO): Calcium oxide.
  • Cain, W.S., et al.: Sensory and associated reactions to mineral dusts: sodium borate, calcium oxide, and calcium sulfate. J. Occup. Environ. Hyg. 1(4): 222-236, 2004.
  • Pohanish, R.P. (editor): Calcium Oxide. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 1. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 468-470.
  • Spoo, J. and Elsner, P.: Cement burns: a review 1960-2000. Contact Dermatitis 45(2): 68-71, 2001.
  • Winder, C. and Carmody, M.: The dermal toxicity of cement. Toxicol. Ind. Health 18(7): 321-331, 2002.

Date Last Revised: 07/20/2006

Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):

Federal OSHA and OSHA State Plan personnel submitting samples to the OSHA Salt Lake Technical Center Laboratory for calcium oxide analysis must use the tared gravimetric sampling media described immediately below.

  • sampling media: Tared 37-mm diameter low-ash polyvinyl chloride filter
    maximum volume: 960 Liters
    minimum volume: 480 Liters
    maximum flow rate: 2.0 L/min
    current analytical method: Gravimetric
    method reference: OSHA Analytical Method (OSHA PV2121)
    method classification: Partially Validated
    note: OSHA personnel can obtain tared sampling media from the Salt Lake Technical Center.
    note: If the net weight of the sample yields a concentration below the standard for the substance, the Salt Lake Technical Center will perform no further work on that sample. If the net weight corresponds to an amount greater than the standard, the sample may be analyzed for the appropriate element and the result reported as the substance.
    alternate elemental analytical method: Atomic Absorption Spectroscopy; AAS
    method reference: OSHA Analytical Method (OSHA ID-121)
    method classification: Fully Validated
    note: When analysis of a compound is requested, an elemental analysis is performed and reported as the compound.

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