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Coal tar pitch volatiles
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 65996–93–2
NIOSH REL: 0.1 mg/m3 (cyclohexane-extractable fraction) TWA; NIOSH considers coal tar pitch volatiles to be potential occupational carcinogens as defined by the OSHA carcinogen policy [29 CFR 1990].
Current OSHA PEL: 0.2 mg/m3 (benzene-soluble fraction) TWA
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 0.2 mg/m3 (benzene-soluble fraction) TWA, A1
Description of Substance: Black or dark-brown amorphous residue.
LEL: . . Unknown
Original (SCP) IDLH: 700 mg/m3 [*Note: “Effective” IDLH = 400 mg/m3 — see discussion below.]
Basis for original (SCP) IDLH: Redmond et al. [1972] have shown that the major health effects resulting from long-term repeated exposure to coal tar pitch volatiles (CTPV) are cancer of the lung, kidney, and skin; however, no studies have been made on carcinogenic effects by any route from single short-term exposure to CTPV that could relate to a 30-minute IDLH. Therefore, reliance must be placed on comparative data of single versus repeated carcinogenic doses of benzo(a)pyrene [B(a)P], a known component of CTPV. Bingham [1971] reported that B(a)P applied in a single dose of 2 mg to the skin of mice yielded tumors in 10% to 20% of the animals whereas 0.01 mg B(a)P applied in a noncarcinogenic solvent applied to the skin 3 times/week for 50 weeks yielded tumors in 50% of the animals. Thus, a single dose producing about 1/3 the number of tumors was 200 times the repeated 3 times/week dose. Using this factor and the value of 0.6 mg/m3 CTPV reported by Mazumdar et al. [1975] as safe for coke oven workers, a total dose IDLH of 120 mg CTPV (as benzene solubles) is calculated; by using 7.5 liters as the minute volume of coke oven workers and a 75% lung retention of CTPV a 30-minute IDLH is calculated to be about 700 mg/m3 (as benzene solubles). However, because of the assigned protection factor afforded by each device, 400 mg/m3 (i.e., 2,000 × the PEL) is the concentration above which only the “most protective” respirators are permitted.
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 |
|---|---|---|---|---|---|---|
| Pyrene Rat |
Potapova et al. 1971 | 170 mg/m3 | —– | ? | ? | ? |
Lethal dose data:
| Species | Reference | Route | LD50(mg/kg) | LDLo(mg/kg) | Adjusted LD | Derived value |
|---|---|---|---|---|---|---|
| Pyrene Rat Mouse |
Potapova et al. 1971 Potapova et al. 1971 |
oral oral |
2,700 800 |
—– —– |
18,900 mg/m3 5,600 mg/m3 |
1,890 mg/m3 560 mg/m3 |
| Anthracene Mouse |
Nogochy 1969 | oral | —– | >17,000 | >119,000 mg/m3 | >11,900 mg/m3 |
| Phenanthrene Mouse |
Rakhmanina 1964 | oral | 700 | —– | 4,900 mg/m3 | 490 mg/m3 |
Other animal data: The major health effects resulting from long-term repeated exposure to coal tar pitch volatiles (CTPV) are cancer of the lung, kidney, and skin [Redmond et al. 1972]; however, no studies have been made on carcinogenic effects by any route from single short-term exposure to CTPV that could relate to a 30-minute IDLH. Therefore, reliance must be placed on comparative data of single versus repeated carcinogenic doses of benzo(a)pyrene [B(a)P], a known component of CTPV. It has been reported that B(a)P applied in a single dose of 2 mg to the skin of mice yielded tumors in 10% to 20% of the animals whereas 0.01 mg B(a)P applied in a noncarcinogenic solvent applied to the skin 3 times/week for 50 weeks yielded tumors in 50% of the animals [Bingham 1971]. Thus, a single dose producing about 1/3 the number of tumors was 200 times the repeated 3 times/week dose. Using this factor and the value of 0.6 mg/m3 CTPV reported as safe for coke oven workers [Mazumdar et al. 1975], a total dose IDLH of 120 mg CTPV (as benzene solubles) is calculated; by using 50 liters as the minute volume of workers and 100% lung retention of CTPV, a 30-minute IDLH is calculated to be about 80 mg/m3 (as benzene solubles).
Human data: None relevant for use in determining the revised IDLH.
| Revised IDLH: 80 mg/m3 (as the benzene-soluble fraction)Basis for revised IDLH: The revised IDLH for coal tar pitch volatiles is 80 mg/m3 (as the benzene-soluble fraction) based on toxicity data in animals [Bingham 1971; Mazumdar et al. 1975; Redmond et al. 1972] (see discussion above). [Note: NIOSH recommends as part of its carcinogen policy that the “most protective” respirators be worn for coal tar pitch volatiles at concentrations above 0.1 mg/m3 (cyclohexane-extractable fraction).] |
REFERENCES:
1. Bingham E [1971]. Thresholds in cancer inductions. If they do exist, do they shift? Arch Environ Health 22:692-695.
2. Mazumdar S, Redmond C, Sollecito W, Sussman N [1975]. An epidemiological study of exposure to coal tar pitch volatiles among coke oven workers. J Air Pollut Control Assoc 25(4):382-389.
3. Nagochy PA [1969]. Comparative study of the toxicity of pure and technical anthracene. Gig Tr Prof Zabol 13(5):59 (in Russian).
4. Potapova AN, Kapitulsky VB, et al. [1971]. Toxicological evaluation of pyrene. Gig Tr Prof Zabol 15(2):59 (in Russian).
5. Rakhmanina NL [1964]. Establishing standards for the phenanthrene and pyrene contents in water bodies. Gig Sanit 29(6):19-23 (translated).
6. Redmond CK, Ciocco A, Lloyd JW, Rush HW [1972]. Long-term mortality study of steel workers. VI. Mortality from malignant neoplasms among coke oven workers. J Occup Med 14(8):621-629.