Pentaborane

CAS number: 19624–22–7

NIOSH REL: 0.005 ppm (0.01 mg/m³) TWA, 0.015 ppm (0.03 mg/m³) STEL

Current OSHA PEL: 0.005 ppm (0.01 mg/m³) TWA

1989 OSHA PEL: 0.005 ppm (0.01 mg/m³) TWA, 0.015 ppm (0.03 mg/m³) STEL

1993-1994 ACGIH TLV: 0.005 ppm (0.013 mg/m³) TWA,

0.015 ppm (0.039 mg/m³) STEL

Description of substance: Colorless liquid with a pungent odor like sour milk.

LEL: . . 0.42% (10% LEL, 420 ppm)

Original (SCP) IDLH: 3 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the mouse 4-hour LC₅₀ of 3 ppm [Jacobson 1958 cited by ACGIH 1971].

Existing short-term exposure guidelines: American Industrial Hygiene Association [AIHA 1966] Emergency Exposure Limits (EELs):

5 minute EEL: 25 ppm

15-minute EEL: 8 ppm

30-minute EEL: 4 ppm

60-minute EEL: 2 ppm

ACUTE TOXICITY DATA:

Lethal concentration data:

Species	Reference	LC50 (ppm)	LCLo (ppm)	Time	Adjusted 0.5-hr LC (CF)	Derived value
Mouse Rat Mouse Dog Monkey Rat Mouse Rat Mouse Rat Mouse Rat Mouse	Jacobson 1958 Levinskas et al. 1958 Levinskas et al. 1958 Weeks et al. 1964 Weeks et al. 1964 Weir et al. 1964 Weir et al. 1964 Weir et al. 1964 Weir et al. 1964 Weir et al. 1964 Weir et al. 1964 Weir et al. 1964 Weir et al. 1964	3 6 3.4 35 244 67 40 31 19 15 11 10 6	----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----	4 hr 4 hr 4 hr 15 min 2 min 5 min 5 min 15 min 15 min 30 min 30 min 1 hr 1 hr	6 ppm (2.0) 12 ppm (2.0) 6.8 ppm (2.0) 28 ppm (0.79) 100 ppm (0.41) 37 ppm (0.55) 22 ppm (0.55) 24 ppm (0.79) 15 ppm (0.79) 15 ppm (1.0) 11 ppm (1.0) 13 ppm (1.25) 7.5 ppm (1.25)	0.6 ppm 1.2 ppm 0.7 ppm 2.8 ppm 10 ppm 3.7 ppm 2.2 ppm 2.4 ppm 1.5 ppm 1.5 ppm 1.1 ppm 1.3 ppm 0.8 ppm

Human data: None relevant for use in determining the revised IDLH.

Revised IDLH: 1 ppm Basis for revised IDLH: The revised IDLH for pentaborane is 1 ppm based on acute inhalation toxicity data in animals [Jacobson 1958; Levinskas et al. 1958; Weir et al. 1964].

REFERENCES:

1. ACGIH [1971]. Pentaborane. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 197.

2. AIHA [1966]. Emergency exposure limits. American Industrial Hygiene Association, Toxicology Committee. Am Ind Hyg Assoc J 27:193-195.

3. Jacobson KH [1958]. Toxicity of borane fuels. In: Transactions of the symposium on health hazards of military chemicals. Army Chemical Center, MD: U.S. Army Chemical Warfare Laboratories, Directorate of Medical Research. CWL Special Publication 2-10, pp. 55-60.

4. Levinskas GJ, Paslian MR, Bleckman WR [1958]. Chronic toxicity of pentaborane vapor. Am Ind Hyg Assoc J 19:46-53.

5. Weeks MH, Burke DG, Bassett EE, Johnson JR, Christensen MK [1964]. Pentaborane: relationship between inhaled lethal and incapacitating dosages in animals. J Pharmacol Exp Ther 145:382-385.

6. Weir FW, Seabaugh VM, Mershon MM, Burke DG, Weeks MH [1964]. Short exposure inhalation toxicity of pentaborane in animals. Toxicol Appl Pharmacol 6:122-131.