Phenylhydrazine

CAS number: 100–63–0

NIOSH REL: 0.14 ppm (0.6 mg/m³) 2-hr CEILING [skin]; NIOSH considers phenylhydrazine to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 5 ppm (22 mg/m³) TWA [skin]

1989 OSHA PEL: 5 ppm (20 mg/m³) TWA, 10 ppm (45 mg/m³) STEL [skin]

1993-1994 ACGIH TLV: 0.1 ppm (0.44 mg/m³) TWA [skin], A2

Description of substance: Colorless to pale-yellow liquid or solid (below 67°F) with a faint, aromatic odor.

LEL:. . Unknown

Original (SCP) IDLH*: 295 ppm [*Note: "Effective" IDLH = 250 ppm -- see discussion below.]

Basis for original (SCP) IDLH: No data on acute or chronic inhalation toxicity are available on which to base the IDLH. Systemic effects described by Patty [1963] were caused by chronic exposures from oral dosing. NIOSH [1976] cited a rat oral LD₅₀ of 188 mg/kg [Ekshtat 1965] which provides a calculated estimate of 1,300 mg/m³ (295 ppm) for the IDLH. Because of the assigned protection factor afforded by each device, however, 50 ´ the OSHA PEL of 5 ppm (i.e., 250 ppm) is the concentration above which only the "most protective" respirators are permitted.

Short-term exposure guidelines: None developed

ACUTE TOXICITY DATA:

Lethal dose data:

Species	Reference	Route	LD50 (mg/kg)	LDLo (mg/kg)	Adjusted LD	Derived value
Rat Mouse Rabbit G. pig Dog	Ekshtat 1965 Ekshtat 1965 Ekshtat 1965 Ekshtat 1965 Ekshtat 1965	oral oral oral oral oral	188 175 80 80 200-250	----- ----- ----- ----- -----	293 ppm 273 ppm 125 ppm 125 ppm 312-390 ppm	29 ppm 27 ppm 13 ppm 13 ppm 31-39 ppm

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

Revised IDLH: 15 ppm Basis for revised IDLH: No inhalation toxicity data are available on which to base an IDLH for phenylhydrazine. Therefore, the revised IDLH for phenylhydrazine is 15 ppm based on acute oral toxicity data in animals [Ekshtat 1965]. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for phenyl hydrazine at concentrations above 0.14 ppm.]

REFERENCES:

1. Ekshtat BY [1965]. Maximum permissible concentrations of hydrazine hydrate and phenylhydrazine in water bodies. Gig Sanit 30(8):191-197 (translated).

2. NIOSH [1976]. MV89250. Hydrazine, phenyl-. In: Registry of toxic effects of chemical substances, 1976 ed. Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. 76-191, p. 598.

3. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., pp. 2227-2228.