Oxygen difluoride

CAS number: 7783–41–7

NIOSH REL: 0.05 ppm (0.1 mg/m³) CEILING

Current OSHA PEL: 0.05 ppm (0.1 mg/m³) TWA

1989 OSHA PEL: 0.05 ppm (0.1 mg/m³) CEILING

1993-1994 ACGIH TLV: 0.05 ppm (0.11 mg/m³) CEILING

Description of substance: Colorless gas with a peculiar, foul odor.

LEL: . . Nonflammable Gas

Original (SCP) IDLH: 0.5 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statements by Deichmann and Gerarde [1969] that oxygen difluoride is a strong irritant to the entire respiratory tract and causes pulmonary edema and hemorrhage when inhaled for a few hours at 0.5 ppm. Development of pulmonary signs leading to death may be delayed several hours after the exposure [Deichmann and Gerarde 1969]. In addition, AIHA [1967] reported that the Committee on Toxicology of the National Research Council recommended an Emergency Exposure Limit (EEL) of 0.5 ppm for a 10-minute exposure. This EEL is supposed to be for exposures that are "rare in the lifetime of an individual and permit some degree of reversible injury short of incapacitation" [Smyth 1966].

Existing short-term exposure guidelines: National Research Council (NRC) Emergency Exposure Limits (EELs) recommended to military and space agencies [Smyth 1966]:

10-minute EEL: 0.5 ppm

30-minute EEL: 0.2 ppm

60-minute EEL: 0.1 ppm

ACUTE TOXICITY DATA:

Lethal concentration data:

Species	Reference	LC50 (ppm)	LCLo (ppm)	Time	Adjusted 0.5-hr LC (CF)	Derived value
Rat Mouse Dog Monkey	Darmer et al. 1972 Darmer et al. 1972 Darmer et al. 1972 Darmer et al. 1972	2.6 1.5 26 16	----- ----- ----- -----	1 hr 1 hr 1 hr 1 hr	3.3 ppm (1.25) 1.9 ppm (1.25) 33 ppm (1.25) 20 ppm (1.25)	0.3 ppm 0.2 ppm 3.3 ppm 2.0 ppm

Human data: Oxygen difluoride is a strong irritant to the entire respiratory tract and causes pulmonary edema and hemorrhage when inhaled for a few hours at 0.5 ppm [Deichmann and Gerarde 1969].

Revised IDLH: 0.5 ppm [Unchanged] Basis for revised IDLH: Based on acute inhalation toxicity data in humans [Deichmann and Gerarde 1969], the original IDLH for oxygen difluoride (0.5 ppm) is not being revised at this time.

REFERENCES:

1. AIHA [1967]. Oxygen difluoride. In: Hygienic guide series. Am Ind Hyg Assoc J 28:194-196.

2. Darmer KI Jr, Haum CC, MacEwen JD [1972]. The acute inhalation toxicology of chlorine pentafluoride. Am Ind Hyg Assoc J 33:661-668.

3. Deichmann WB, Gerarde HW [1969]. Oxygen difluoride (OF₂). In: Toxicology of drugs and chemicals. New York, NY: Academic Press, Inc., p. 444.

4. Smyth HF Jr [1966]. Military and space short-term inhalation standards. Arch Environ Health 12:488-490.