Formic acid

IDLH Documentation

CAS number: 64­18­6

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 Unpublished data.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 20:517­531.
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