Formic acid

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-hr LC (CF)	Derived value
Rat Mouse	Gig Tr Prof Zabol 1963 Gig Tr Prof Zabol 1963	7,853 3,246	----- -----	15 min 15 min	6,204 ppm (0.79) 2,564 ppm (0.79)	620 ppm 256 ppm

Lethal dose data:

Species	Reference	Route	LD50 (mg/kg)	LDLo (mg/kg)	Adjusted LD	Derived value
Rat Mouse Dog	Gig Tr Prof Zabol 1963 Gig Tr Prof Zabol 1963 von Oettingen 1959	oral oral oral	1,100 700 4,000	----- ----- -----	4,031 ppm 2,565 ppm 14,659 ppm	403 ppm 256 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 Unpublished data.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.