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Xylene (o-, m-, p-isomers)

May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS numbers: 95-47-6 (o-isomer), 108-38-3 (m-isomer), 106-42-3 (p-isomer)

NIOSH REL: 100 ppm (435 mg/m3) TWA, 150 ppm (655 mg/m3) STEL

Current OSHA PEL: 100 ppm (435 mg/m3) TWA

1989 OSHA PEL: 100 ppm (435 mg/m3) TWA, 150 ppm (655 mg/m3) STEL

1993-1994 ACGIH TLV: 100 ppm (434 mg/m3) TWA, 150 ppm (651 mg/m3) STEL

Description of substance: Colorless liquid with an aromatic odor.

LEL: . . 0.9-1.1% (10% LEL, 900-1,100 ppm)

Original (SCP) IDLH: 1,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the following statements by ANSI [1971]. “Exposure at 1,000 ppm for 5 minutes or less will probably allow self-rescue with no irreversible injury. Higher concentrations or longer exposure periods can cause eye and respiratory tract irritation, and the beginning of narcotic effects which may limit self-rescue ability. This information is based on human experience and extrapolation from animal data.”

Existing short-term exposure guidelines: National Research Council [NRC 1984] Emergency Exposure Guidance Levels (EEGLs):

1-hour EEGL: 200 ppm

24-hour EEGL: 100 ppm


Lethal concentration data:

Species Reference LC50(ppm) LCLo(ppm) Time Adjusted 0.5-hrLC (CF) Derived value
o-Xylene Rat Cameron et al. 1938 —– 6,125 12 hr 73,500 ppm (2.9) 7,350 ppm
o-Xylene Human Gekkan Yakuji 1980 —– 6,125 12 hr 73,500 ppm (2.9) 7,350 ppm
m-Xylene Mouse Cameron et al. 1938 —– 2,010 24 hr 7,236 ppm (3.6) 724 ppm
m-Xylene Rat Smyth et al. 1962 —– 8,000 4 hr 16,000 ppm (2.0) 1,600 ppm
p-Xylene Mouse Arch Exp Pathol Pharmacol 1929 —– 3,401 ? ? ?
p-Xylene Rat Harper et al. 1977 4,550 —– 4 hr 9,100 ppm (2.0) 910 ppm
Xylene Human Morley et al. 1970 —– 10,000 18 hr 33,000 ppm (3.3) 3,300 ppm
Xylene Rat NPIRI 1974 5,000 —– 4 hr 10,000 ppm (2.0) 1,000 ppm
Xylene G. pig Smyth and Smyth 1928 —– 450 ? ? ?

Other animal data: RD50 (mouse): 1,467 ppm [DeCeaurriz et al. 1981].

Other human data: It has been reported that 1,000 ppm for 5 minutes or less will probably allow self-rescue with no irreversible injury [ANSI 1971]. Volunteers found 200 ppm to be definitely irritating to the eyes, nose, and throat [Nelson et al. 1943]. Reaction time was not affected in 23 volunteers exposed to 100 or 200 ppm for 3 to 7 hours [Ogata et al. 1970]. No noticeable changes in reaction time or short-term memory tests were seen in 15 volunteers exposed to 100 or 300 ppm for 70 minutes [Gamberale et al. 1978].


1. Arch Exp Pathol Pharmakol [1929]. Toxicity of various hydrocarbon vapors; 143:223-233 (in German).

2. ANSI [1971]. American national standard, acceptable concentrations of xylene (dimethyl benzene). New York, NY: American National Standards Institute, Inc., ANSI Z37.10-1971, p. 7.

3. Cameron GR, Paterson JLH, de Saram GSW, Thomas JC [1938]. The toxicity of some methyl derivatives of benzene with special reference to pseudocumene and heavy coal tar naphtha. J Pathol Bacteriol 46:95-107.

4. DeCeaurriz JC, Micillino JC, Bonnet P, Guenier JP [1981]. Sensory irritation caused by various industrial airborne chemicals. Toxicol Lett 9(2):137-143.

5. Gamberale F, Annwall G, Hultengren M [1978]. Exposure to xylene and ethylbenzene. III. Effects on central nervous functions. Scand J Work Environ Health 4:204-211.

6. Gekkan Yakuji (Pharmaceuticals Monthly) [1980]; 22(5):883-889 (in Japanese).

7. Harper C, Drew RT, Fouts JR [1977]. Benzene and p-xylene: a comparison of inhalation toxicities and in vitro hydroxylations. In: Biological reactive intermediates, formulation, toxicity, and inactivation. Proceedings of the International Conference, Twiku, Finland, 1975. New York, NY: Plenum Publishing Corporation, pp. 302-311.

8. Morley R, Eccleston DW, Douglas CP, Greville WEJ, Scott DJ, Anderson J [1970]. Xylene poisoning: a report on one fatal case and two cases of recovery after prolonged unconsciousness. Br Med J 3:442-443.

9. Nelson KW, Ege JF, Ross M, Woodman LE, Silverman L [1943]. Sensory response to certain industrial solvent vapors. J Ind Hyg Toxicol 25(7):282-285.

10. NPIRI [1974]. Raw materials data handbook, physical and chemical properties, fire hazard and health hazard data. Vol. 1. Organic solvents. Bethlehem, PA: National Printing Ink Research Institute, p. 123.

11. NRC [1984]. Emergency and continuous exposure limits for selected airborne contaminants. Vol. 2. Washington, DC: National Academy Press, Committee on Toxicology, Board on Toxicology and Environmental Health Hazards, Commission on Life Sciences, National Research Council, pp. 113-123.

12. Ogata M, Tomokuni K, Tatatsuka Y [1970]. Urinary excretion of hippuric acid and m- or p-methylhippuric acid in the urine of persons exposed to vapours of toluene and m- and p-xylene as a test of exposure. Br J Ind Med 27:43-50.

13. Smyth HF, Smyth HF Jr [1928]. Inhalation experiments with certain lacquer solvents. J Ind Hyg 10(8):261-271.

14. Smyth HF, Carpenter CP, Weil CS, Pozzani UC, Striegel JA [1962]. Range-finding toxicity data: list VI. Am Ind Hyg Assoc J 23:95-107.