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Manganese compounds (as Mn)
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 7439–96–5 (Metal)
NIOSH REL: 1 mg/m3 TWA, 3 mg/m3 STEL
Current OSHA PEL: 5 mg/m3 CEILING
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 5 mg/m3 TWA
Description of substance: Varies
Original (SCP) IDLH*: No Evidence [*Note: “Effective” IDLH = 10,000 mg Mn/m3 — see discussion below.]
Basis for original (SCP) IDLH: The available toxicological data do not indicate that exposure to a high concentration of manganese could impede escape within 30 minutes. For this draft technical standard, therefore, respirators have been assigned on the basis of the assigned protection factor afforded by each device up to 2,000 ´ the OSHA PEL (2,000 ´ 5 mg Mn/m3 is 10,000 mg Mn/m3; only the “most protective” respirators are permitted for use in concentrations exceeding 10,000 mg Mn/m3).
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA:
Lethal dose data:
| Species | Reference | Route | LD50(mg/kg) | LDLo(mg/kg) | Adjusted LD | Derived value |
|---|---|---|---|---|---|---|
| Mn Rat | Marhold 1972 | oral | 9,000 | —– | 63,000 mg Mn/m3 | 6,300 mg Mn/m3 |
| MnC4H6O4 Rat | Marhold 1977 | oral | 2,940 | —– | 6,586 mg Mn/m3 | 659 mg Mn/m3 |
| MnCl2 Mouse | Gupta et al. 1981 | oral | 1,715 | —– | 5,282 mg Mn/m3 | 528 mg Mn/m3 |
Human data: Chronic exposures to workers averaging 47 mg/m3 caused manganese poisoning, while no cases occurred at exposures less than 30 mg/m3 [Flinn et al. 1940]. Chronic exposure to concentrations averaging 210 mg/m3 have been associated with pneumonia [Lloyd-Davies 1946]. Workers chronically exposed to concentrations of manganese dust averaging 20 mg/m3 showed signs of manganism [Smyth et al. 1973].
| Revised IDLH: 500 mg Mn/m3Basis for revised IDLH: The revised IDLH for manganese is 500 mg Mn/m3 based on acute inhalation toxicity data in animals [Gupta et al. 1981]. This may be a conservative value due to the lack of relevant acute toxicity data for workers. |
REFERENCES:
1. Flinn RH, Neal PA, Reinhart WH, Dallavalle JM, Fulton WB, Dooley AE [1940]. Chronic manganese poisoning in an ore-crushing mill. Public Health Bulletin 247:1-77.
2. Gupta PK, Murthy RC, Chandra SV [1981]. Toxicity of endosulfan and manganese chloride: cumulative toxicity rating. Toxicol Lett 7:221-227.
3. Lloyd-Davies TA [1946]. Manganese pneumonitis. Br J Ind Med 3:111-135.
4. Marhold JV [1972]. Sbornik vysledku toxixologickeho vysetreni latek a pripravku. Czechoslovakia: Institut Pro Vychovu Vedoucicn Pracovniku Chemickeho Prumyclu Praha, p. 21 (in Czechoslovakian).
5. Marhold JV [1977]. Personal communication. Pardubice, Czechoslovakia: VUOS, 539-18, 3/29/77.
6. Smyth LT, Ruhf RC, Whitman NE, Dugan T [1973]. Clinical manganism and exposure to manganese in the production and processing of ferromanganese alloy. J Occup Med 15:101-109.