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tert-Butyl chromate

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

CAS number: 1189–85–1

NIOSH REL: 0.001 mg Cr(VI)/m3 TWA; NIOSH considers tert-butyl chromate to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 0.1 mg CrO3/m3 CEILING [skin]

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.1 mg CrO3/m3 CEILING [skin]

Description of Substance: Liquid.

LEL: . . Unknown

Original (SCP) IDLH: 30 mg CrO3/m3

Basis for original (SCP) IDLH: Very little toxicological data are available concerning the effects produced by exposure to tert-butyl chromate. Because AIHA [1965] reported that the severity of the health hazard is low for acute exposure to chromic acid, by analogy it is assumed that the hazard is also low for acute exposure to tert-butyl chromate. Therefore, the chosen IDLH is based on an analogy with chromic acid and chromates, which has an IDLH of 30 mg/m3 (as CrO3).

Short-term exposure guidelines: None developed


Animal or human data: None relevant for use in determining the revised IDLH.

Revised IDLH: 15 mg Cr(VI)/m3 [Unchanged]

Basis for revised IDLH: Due to the lack of toxicity data specifically for tert-butyl chromate, the revised IDLH for tert-butyl chromate is 15 mg Cr(VI)/m3 (which is roughly equivalent to the original IDLH of 30 mg CrO3/m3) based on an analogy to chromic acid and other chromates which have a revised IDLH of 15 mg Cr(VI)/m3. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for tert-butyl chromate at concentrations above 0.001 mg Cr(VI)/m3.]


1. AIHA [1965]. Chromic acid. In: Hygienic guide series. Reprinted in 1965 by the American Industrial Hygiene Association.