o-Dichlorobenzene

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 [1971] that 1,000 ppm was fatal to guinea pigs after 20 hours [Browning 1953]. ACGIH [1971] also reported that Cameron et al. [1937] 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-hr LC (CF)	Derived value
G. pig G. pig Rat	Browning 1953 Cameron et al. 1937 Hollingsworth et al. 1958	----- ----- -----	1,000 800 821	20 hr 24 hr 7 hr	3,450 ppm (3.45) 2,880 ppm (3.6) 1,970 ppm (2.4)	345 ppm 288 ppm 197 ppm

Lethal dose data:

Species	Reference	Route	LD50 (mg/kg)	LDLo (mg/kg)	Adjusted LD	Derived value
Rat G. pig Rabbit Mouse	Ben-Dyke et al. 1970 Patty 1963 Thomson 1976/77 Yakkyoku 1981	oral oral oral oral	500 2,000 500 4,386	----- ----- ----- -----	573 ppm 2,291 ppm 573 ppm 5,025 ppm	57 ppm 229 ppm 57 ppm 503 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 ppm Basis 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.

REFERENCES:

1. ACGIH [1971]. o-Dichlorobenzene. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 76.

2. Ben-Dyke R, Sanderson DM, Noakes DN [1970]. Acute toxicity data for pesticides (1970). World Review of Pesticide Control 9:119-127.

3. Browning E [1953]. Toxicity of industrial organic solvents. New York, NY: Chemical Publishing Company, p. 190.

4. Cameron GR, Thomas JC, Ashmore SA, Buchan JL, Warren EH, Hughes AWM [1937]. The toxicity of certain chlorine derivatives of benzene, with special reference to o-dichlorobenzene. J Pathol Bacteriol 44(2):281-296.

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

6. Elkins HB [1959]. The chemistry of industrial toxicology. 2nd ed. New York, NY: John Wiley & Sons, Inc., p. 150.

7. Hollingsworth RL, Rowe VK, Oyen F, Torkelson TR, Adams EM [1958]. Toxicity of o-dichlorobenzene. AMA Arch Ind Health 17:180-187.

8. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1336.

9. Thomson WT [1976/77]. Agricultural chemicals. Fresno, CA: Thomas Publications, 3:32.

10. Yakkyoku (Pharmacy) [1981]; 32:471-474 (in Japanese).