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May 1994
 

Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)


Sodium hydroxide

CAS number: 1310–73–2

NIOSH REL: 2 mg/m3 CEILING

Current OSHA PEL: 2 mg/m3 TWA

1989 OSHA PEL: 2 mg/m3 CEILING

1993-1994 ACGIH: 2 mg/m3 CEILING

Description of substance: Colorless to white, odorless solid (flakes, beads, granular form).

LEL :. . Noncombustible Solid

Original (SCP) IDLH: 250 mg/m3

Basis for original (SCP) IDLH: No data on acute inhalation toxicity are available on which to base the IDLH for sodium hydroxide. The chosen IDLH, therefore, has been estimated from the mouse intraperitoneal LD50 of 40 mg/kg [Nofre et al. 1963 cited by NIOSH 1974].

Existing short-term exposure guidelines: National Research Council [NRC 1984] Emergency Exposure Guidance Levels (EEGLs):

10-minute EEGL: 2 mg/m3

30-minute EEGL: 2 mg/m3

60-minute EEGL: 2 mg/m3

ACUTE TOXICITY DATA:

Lethal dose data:

 

SpeciesReferenceRouteLD50

(mg/kg)

LDLo

(mg/kg)

Adjusted LDDerived value
RabbitFazekas 1937oral-----5003,500 mg/m3 350 mg/m3
MouseNofre et al. 1963 i.p.40-----280 mg/m328 mg/m3

Human data: Workplace concentrations ranging from 2 to 8 mg/m3 have been associated with irritation of the respiratory system [Ott et al. 1977].

 

Revised IDLH: 10 mg/m3

Basis for revised IDLH: The revised IDLH for sodium hydroxide is 10 mg/m3 based on acute inhalation toxicity data in workers [Ott et al. 1977]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 8 mg/m3.

REFERENCES:

1. Fazekas JG [1937]. Die veränderungen des blutchemismus bei experimenteller laugenvergiftung. Arch Exp Pathol Pharmakol 184:587-604 (in German).

2. NIOSH [1974]. WB49000. Sodium hydroxide. In: The toxic substances list, 1974 ed. Rockville, MD: U.S. Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. 74-134, p. 721.

3. Nofre C, Dufour H, Cier A [1963]. Toxicite generale comparee des anions mineraux chez la souris. In: Comp Rend Hebdom (Juillet 17, 1963), pp. 791-794 (in French). [From NIOSH [1974]. WB49000. Sodium hydroxide. In: The toxic substances list, 1974 ed. Rockville, MD: U.S. Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. 74-134, p. 721.]

4. NRC [1984]. Emergency and continuous exposure limits for selected airborne contaminants. Vol. 2. Washington, DC: National Academy Press, Committee on Toxicology, Board on Toxicology and Environmental Health Hazards, Commission on Life Sciences, National Research Council, pp. 87-94.

5. Ott MG, Gordon HL, Schneider EJ [1977]. Mortality among employees chronically exposed to caustic dust. J Occup Med 17:813-816.

 
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