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Formic acid
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 64–18–6
NIOSH REL: 5 ppm (9 mg/m3) TWA
Current OSHA PEL: 5 ppm (9 mg/m3) TWA
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 5 ppm (9.4 mg/m3) TWA, 10 ppm (19 mg/m3) STEL
Description of Substance: Colorless liquid with a pungent, penetrating odor.
LEL(90% solution): 18% (10% LEL (90% solution), 18,000 ppm)
Original (SCP) IDLH: 30 ppm
Basis for original (SCP) IDLH: Because no data on acute inhalation toxicity are available on which to base an IDLH for formic acid, the chosen IDLH is based on an analogy with formaldehyde, which has an IDLH of 30 ppm.
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA
Lethal concentration data:
| Species | Reference | LC50(ppm) | LCLo(ppm) | Time | Adjusted 0.5-hrLC (CF) | Derivedvalue |
|---|---|---|---|---|---|---|
| RatMouse | Gig Tr Prof Zabol 1963Gig Tr Prof Zabol 1963 | 7,8533,246 | ———- | 15 min15 min | 6,204 ppm (0.79)2,564 ppm (0.79) | 620 ppm256 ppm |
Lethal dose data:
| Species | Reference | Route | LD50(mg/kg) | LDLo(mg/kg) | Adjusted LD | Derived value |
|---|---|---|---|---|---|---|
| RatMouse
Dog |
Gig Tr Prof Zabol 1963Gig Tr Prof Zabol 1963
von Oettingen 1959 |
oraloral
oral |
1,100700
4,000 |
———-
—– |
4,031 ppm2,565 ppm
14,659 ppm |
403 ppm256 ppm
1,466 ppm |
Human data: Workers exposed to about 15 ppm have complained of nausea [Fahy and Elkins 1954].
| Revised IDLH: 30 ppm [Unchanged]Basis for revised IDLH: Based on acute inhalation toxicity data in animals [Gig Tr Prof Zabol 1963], a value of about 250 ppm would have been appropriate for formic acid. However, the original IDLH for formic acid (30 ppm) is not being revised at this time. |
REFERENCES:
1. Fahy JP, Elkins HB [1954]. Unpublished data. [From: ACGIH [1986]. Formic acid. In: Documentation of the threshold limit values and biological exposure indices. 5th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 279.].
2. Gig Tr Prof Zabol [1963]; 23(12):49 (in Russian).
3. von Oettingen WF [1959]. The aliphatic acids and their esters toxicity and potential dangers. AMA Arch Ind Health 20:517-531.