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p-Nitrochlorobenzene
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 100–00–5
NIOSH REL: None established; NIOSH considers p-nitrochlorobenzene to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990] that may be absorbed through the skin.
Current OSHA PEL: 1 mg/m3 TWA [skin]
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 0.64 mg/m3 (0.1 ppm) TWA [skin]
Description of substance: Yellow, crystalline solid with a sweet odor.
LEL: . . . Unknown
Original (SCP) IDLH: 1,000 mg/m3
Basis for original (SCP) IDLH: No data on acute inhalation toxicity are available on which to base an IDLH for p-nitrochlorobenzene. The chosen IDLH, therefore, is based on an analogy with nitrobenzene, which has an IDLH of 200 ppm. [Note: A concentration of 200 ppm nitrobenzene is equivalent to about 1,000 mg/m3 p-nitrochlorobenzene.]
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA:
Lethal concentration data:
| Species | Reference | LC50 | LCLo | Time | Adjusted 0.5-hrLC (CF) | Derived value |
|---|---|---|---|---|---|---|
| Cat | Watrous & Schultz 1950 | 164 mg/m3 | —– | 7 hr | 393 mg/m3 (2.4) | 39 mg/m3 |
Lethal dose data:
| Species | Reference | Route | LD50(mg/kg) | LDLo(mg/kg) | Adjusted LD | Derived value |
|---|---|---|---|---|---|---|
| Rat | Back et al. 1972 | oral | 812 | —– | 5,684 mg/m3 | 568 mg/m3 |
| Mouse | Back et al. 1972 | oral | 1,414 | —– | 9,898 mg/m3 | 990 mg/m3 |
| Mouse | Izmerov et al. 1982 | oral | 440 | —– | 3,080 mg/m3 | 308 mg/m3 |
| Rat | Sziza & Magos 1959 | oral | 420 | —– | 2,940 mg/m3 | 294 mg/m3 |
Other animal data: Exposures of cats and guinea pigs to 87 mg/m3 for 8 hours/day for 6 weeks resulted in methemoglobinemia and slight anemia [Watrous and Schultz 1950].
Human data: Workers exposed intermittently for 0.5 to 1 hour over many months to concentrations ranging from 7 to 400 mg/m3 (average of 90 mg/m3) had only vague complaints of tiredness, loss of appetite, headache, and afternoon fatigue [Watrous and Schultz 1950]. Because of the strong and disagreeable odor, these workers voluntarily wore respiratory protection when exposed to the higher concentrations [Watrous and Schultz 1950].
| Revised IDLH: 100 mg/m3Basis for revised IDLH: The revised IDLH for p-nitrochlorobenzene is 100 mg/m3 based on subchronic inhalation toxicity data in workers [Watrous and Schultz 1950] and animals [Watrous and Schultz 1950]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 100 mg/m3. [Note: NIOSH recommends as part of its carcinogen policy that the “most protective” respirators be worn for p-nitrochlorobenzene at any detectable concentration.] |
REFERENCES:
1. Back KC, Thomas AA, MacEwen JD [1972]. Reclassification of materials listed as transportation health hazards. Wright-Patterson Air Force Base, OH: 6570th Aerospace Medical Research Laboratory, Report No. TSA-20-72-3, pp. A-270 to A-271.
2. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 92.
3. Sziza M, Magos I [1959]. Toxikologische untersuchung einiger in der ungarischen industrie zur anwendung gelangenden aromatischen nitroverbindungen. Arch Gewerbepath Gewerbehyg 17:217-226 (in German).
4. Watrous RM, Schultz HN [1950]. Cyclohexylamine, p-chloronitrobenzene, 2-aminopyridine: toxic effects in industrial use. Ind Med Surg 19:317-320.