Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 95–50–1
NIOSH REL: 50 ppm (300 mg/m3) CEILING
Current OSHA PEL: 50 ppm (300 mg/m3) CEILING
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 25 ppm (150 mg/m3) TWA, 50 ppm (301 mg/m3) STEL
Description of Substance: Colorless to pale-yellow liquid with a pleasant, aromatic odor.
LEL:. . 2.2% (10% LEL, 2,200 ppm)
Original (SCP) IDLH: 1,000 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by ACGIH  that 1,000 ppm was fatal to guinea pigs after 20 hours [Browning 1953]. ACGIH  also reported that Cameron et al.  found liver damage in animals after exposure for a few hours at 50 to 800 ppm.
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA
Lethal concentration data:
|Species||Reference||LC50(ppm)||LCLo(ppm)||Time||Adjusted 0.5-hrLC (CF)||Derivedvalue|
|G. pigG. pig
|Browning 1953Cameron et al. 1937
Hollingsworth et al. 1958
|20 hr24 hr
|3,450 ppm (3.45)2,880 ppm (3.6)
1,970 ppm (2.4)
|345 ppm288 ppm
Lethal dose data:
|Species||Reference||Route||LD50(mg/kg)||LDLo(mg/kg)||Adjusted LD||Derived value|
|Ben-Dyke et al. 1970Patty 1963
|573 ppm2,291 ppm
|57 ppm229 ppm
Other animal data: RD50 (mouse), 182 ppm [DeCeaurriz et al. 1981].
Human data: Concentrations up to 100 ppm have been reported to have caused sporadic irritation of the eyes and respiratory tract [Elkins 1959].
|Revised IDLH: 200 ppmBasis for revised IDLH: The revised IDLH for o-dichlorobenzene is 200 ppm based on acute inhalation toxicity data in animals [Hollingsworth et al. 1958]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 100 ppm.|
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