Chromium(III) compounds [as Cr(III)]

CAS number: Varies

NIOSH REL: 0.5 mg/m³ TWA

Current OSHA PEL: 0.5 mg/m³ TWA

1989 OSHA PEL: Same as current PEL

1993­1994 ACGIH TLV: 0.5 mg/m³ TWA

Description of Substance: Varies

Original (SCP) IDLH*: No Evidence [*Note: "Effective" IDLH = 250 mg Cr(III)/m³ -- see discussion below.]

Basis for original (SCP) IDLH: ACGIH [1971] noted that early studies indicated trivalent chromium to be essentially nontoxic [Akatsuka and Fairhall 1934]. The available toxicological data show no evidence that an acute exposure to a high concentration of soluble chromic salts would impede escape or cause any irreversible health effects within 30 minutes. For this draft technical standard, therefore, respirators have been selected on the basis of the assigned protection factor afforded by each device. However, for some particulate substances for which no evidence of an IDLH exists, the determination of allowable respiratory protection based on protection factors may result in the assignment of respirators for concentrations that are not likely to be encountered in the occupational environment. Therefore, for all such particulate substances it has been arbitrarily determined that only the "most protective" respirators are permitted for use in concentrations exceeding 500 × the OSHA PEL; in the case of chromium(III) compounds, 500 × the OSHA PEL of 0.5 mg Cr(III)/m³ is 250 mg Cr(III)/m³.

Short­term exposure guidelines: None developed

ACUTE TOXICITY DATA

Lethal dose data:

Species	Reference	Route	LD50 (mg/kg)	LDLo (mg/kg)	Adjusted LD	Derived value
CrCl3 Rat	Gekkan Yakuji 1980	oral	1,870	-----	4,320 mg Cr(III)/m3	432 mg Cr(III)/m3
CrF3 G. pig	Gekkan Yakuji 1980	oral	150	-----	500 mg Cr(III)/m3	50 mg Cr(III)/m3
Cr(NO3)2 Rat Mouse	Gekkan Yakuji 1980 Sangyo Igaku 1978	oral oral	3,250 110	----- -----	4,961 mg Cr(III)/m3 168 mg Cr(III)/m3	496 mg Cr(III)/m3 17 mg Cr(III)/m3

Human data: It has been reported that trivalent chromium compounds (i.e., chromic salts) have a low order of toxicity and provide little industrial hazard [ACGIH 1971; Akatsuka and Fairhall 1934; Clayton and Clayton 1981]

Revised IDLH: 25 mg Cr(III)/m3 Basis for revised IDLH: No inhalation toxicity data are available on which to base an IDLH for chromium(III) compounds. Therefore, the revised IDLH for chromium(III) compounds is 25 mg Cr(III)/m3 based on acute oral toxicity data in animals [Gekkan Yakuji 1980; Sangyo Igaku 1978]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 25 mg Cr(III)/m3.

REFERENCES:

1. ACGIH [1971]. Chromium (as Cr). In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 56.

2. Akatsuka K, Fairhall LT [1934]. The toxicology of chromium. J Ind Hyg 16:1­28.

3. Clayton GD, Clayton FE, eds. [1981]. Patty's industrial hygiene and toxicology. 3rd rev. ed. Vol. 2A. Toxicology. New York, NY: John Wiley & Sons, Inc., pp. 1593­1596.

4. Gekkan Yakuji (Pharmaceuticals Monthly) [1980]; 22(2):291­298 (in Japanese).

5. Sangyo Igaku (Japanese Journal of Industrial Health) [1978]; 20:590­591 (in Japanese).

CDC home page.

---