Xylene (o-, m-, p-isomers)
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 . “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
ACUTE TOXICITY DATA:
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].
|Revised IDLH: 900 ppmBasis for revised IDLH: The revised IDLH is 900 ppm based on acute inhalation toxicity data in animals [Cameron et al. 1938; DeCeaurriz et al. 1981; Harper et al. 1977; NPIRI 1974]. Although this may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 300 ppm, this value would have otherwise been selected for safety considerations (i.e., being 10% of the lower explosive limit of 0.9% for o-xylene).|
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