Cresol (o, m, p isomers)

CAS numbers: 95­48­7 (o­isomer), 108­39­4 (m­isomer), 106­44­5 (p­isomer)

NIOSH REL: 2.3 ppm (10 mg/m³) TWA

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

1989 OSHA PEL: Same as current PEL

1993­1994 ACGIH TLV: 5 ppm (22 mg/m³) TWA [skin]

Description of Substance: White crystals with a sweet, tarry odor.

LEL(@300 F): 1.4% (10% LEL(@300 F), 1,400 ppm)

Original (SCP) IDLH: 250 ppm

Basis for original (SCP) IDLH: The only quantitative acute inhalation toxicity data available are those cited by Patty [1963]. Patty [1963] reported that rats exposed for 8 hours to a saturated concentration of cresol vapors survived the exposure [Smyth 1956]. The chosen IDLH is based on the isomer with the highest vapor pressure, that of o­cresol, which yields a saturated concentration of 323 ppm at 25 C. The chosen IDLH appears to be conservative because no rats died as a result of this exposure which was for 8 hours. Based on the rat oral LD₅₀ of 207 mg/kg for p­cresol [Biofax 1969 cited by NIOSH 1976], an IDLH of 250 ppm is reasonable.

Short­term exposure guidelines: None developed

ACUTE TOXICITY DATA

Lethal dose data:

Species	Reference	Route	LD50 (mg/kg)	LDLo (mg/kg)	Adjusted LD	Derived value
Cresols Rat Mouse Mouse	Back et al. 1972 Back et al. 1972 Kuroki et al. 1982	oral oral oral	1,454 861 760	----- ----- -----	2,262 ppm 1,339 ppm 1,182 ppm	226 ppm 134 ppm 118 ppm
o-Cresol Rat Rat Mouse	Biofax 1969b Deichmann and Witherup 1944 Gig Tr Prof Zabol 1974	oral oral oral	121 1,350 344	----- ----- -----	188 ppm 2,100 ppm 535 ppm	19 ppm 210 ppm 54 ppm
m-Cresol Rat Rat Mouse	Biofax 1969a Deichmann and Witherup 1944 Gig Tr Prof Zabol 1974	oral oral oral	242 2,020 828	----- ----- -----	376 ppm 3,142 ppm 1,288 ppm	38 ppm 314 ppm 129 ppm
p-Cresol Rat Rat Mouse	Biofax 1969c Deichmann and Witherup 1944 Gig Tr Prof Zabol 1974	oral oral oral	207 1,800 344	----- ----- -----	322 ppm 2,800 ppm 535 ppm	32 ppm 280 ppm 54 ppm

Other animal data: Rats exposed to a saturated concentration of cresol vapors (about 150 to 380 ppm) survived the exposure for 8 hours [Smyth 1956].

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

Revised IDLH: 250 ppm [Unchanged] Basis for revised IDLH: Based on acute inhalation toxicity data in animals [Smyth 1956], the original IDLH for cresol (250 ppm) is not being revised at this time.

REFERENCES:

1. Back KC, Thomas AA, MacEwen JD [1972]. Reclassification of materials listed as transportation health hazards. Wright­Patterson Air Force Base, OH: 6570th Aerospace Medical Research Laboratory, Report No. TSA­20­72­3, pp. A­330 to A­331.

2. Biofax [1969a]. Data sheet 3­5/69. Northbrook, IL: Biofax Industrial Bio­Test Laboratories, Inc.

3. Biofax [1969b]. Data sheet 4­5/69. Northbrook, IL: Biofax Industrial Bio­Test Laboratories, Inc.

4. Biofax [1969c]. Data sheet 5­5/69. Northbrook, IL: Biofax Industrial Bio­Test Laboratories, Inc.

5. Deichmann WB, Witherup S [1944]. Phenol Studies. VI. The acute and comparative toxicity of phenol and o-, m-, and p­cresols for experimental animals. J Pharmacol Exp Ther 80:233­240.

6. Gig Tr Prof Zabol [1974]; 18(2):58­59 (in Russian).

7. Kuroki K, Murakami Y, Osumi T, Kimura T [1982]. A study on acute toxicity of formalin­guaiacol. Kyushu Shika Gakkai Zasshi (Journal of the Kyushu Dental Society) 36(6):932­939 (in Japanese).

8. NIOSH [1976]. GO64750. p­Cresol. 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. 76­191, p. 353.

9. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1390.

10. Smyth HF Jr [1956]. Improved communication: hygienic standards for daily inhalation. Am Ind Hyg Assoc Q 17(2):129­185.

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