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May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 1335–88–2

NIOSH REL: 2 mg/m3 TWA [skin]

Current OSHA PEL: 2 mg/m3 TWA [skin]

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 2 mg/m3 TWA

Description of substance: Colorless to pale-yellow solid with an aromatic odor.

LEL:. . Unknown

Original (SCP) IDLH*: Unknown [*Note: “Effective” IDLH = 20 mg/m3 — see discussion below.]

Basis for original (SCP) IDLH: No toxicological data are available concerning the effects of acute exposures to tetrachloronaphthalene. For this draft technical standard, however, an analogy with other chloronaphthalenes was used, and the respirators have been selected on the basis of the assigned protection factor afforded by each device up to 10 ´ the OSHA PEL of 2 mg/m3 (i.e., 20 mg/m3); only the “most protective” respirators are permitted for use in concentrations exceeding 20 mg/m3.

Short-term exposure guidelines: None developed


Animal data: It has been stated that tetrachloronaphthalene has been shown to be less toxic to the liver than more highly chlorinated derivatives of naphthalene [ACGIH 1986].

Human data: None relevant for use in determining the revised IDLH.


1. ACGIH [1986]. Tetrachloronaphthalene. In: Documentation of the threshold limit values and biological exposure indices. 5th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 562.