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Zirconium compounds (as Zr)

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

CAS number: 7440–67–7 (Metal)

NIOSH REL: 5 mg/m3 TWA, 10 mg/m3 STEL

Current OSHA PEL: 5 mg/m3 TWA

1989 OSHA PEL: 5 mg/m3 TWA, 10 mg/m3 STEL

1993-1994 ACGIH TLV: 5 mg/m3 TWA, 10 mg/m3 STEL

Description of substance: Varies

Original (SCP) IDLH: 500 mg Zr/m3

Basis for original (SCP) IDLH: The available toxicological data indicate that zirconium compounds possess a low order of toxicity. The chosen IDLH has been based on the citation by NIOSH [1976] that a 30-minute exposure to 500 mg/m3 of zirconium nitrate is the lowest concentration of this substance which has been shown to be lethal to rats [Mogilevskaya 1967].

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50 LCLo Time Adjusted 0.5-hr


Derived value
Zr(NO3)2 Rat Mogilevskaya 1967 ----- 500 mg/m3 30 min 212 mg Zr/m3 (1.0) 21 mg Zr/m3

Lethal dose data:

Species Reference Route LD50




Adjusted LD Derived value
ZrF6×2K Mouse Shalganova 1967 oral 98 ----- 221 mg Zr/m3 22 mg Zr/m3
Zr(SO4)2 Rat Cochran et al. 1950 oral 3,500 ----- 7,886 mg Zr/m3 789 mg Zr/m3
ZrOCl2 Mouse Delongeas et al. 1983 oral 1,227 ----- 4,398 mg Zr/m3 440 mg Zr/m3
ZrOCl2 Rat Klimmer & Doll 1964 oral 2,950 ----- 10,573 mg Zr/m3 1,057 mg Zr/m3
ZrCl4 Rat ACGIH 1986 oral 1,688 ----- 4,643 mg Zr/m3 464 mg Zr/m3
ZrCl4 Mouse ACGIH 1986 oral 655 ----- 1,801 mg Zr/m3 180 mg Zr/m3
ZrF4 Rat ACGIH 1986 oral 98 ----- 374 mg Zr/m3 37 mg Zr/m3

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

Revised IDLH: 25 mg Zr/m3

Basis for revised IDLH: The revised IDLH for zirconium compounds is 25 mg Zr/m3 based on acute toxicity data in animals [ACGIH 1986; Mogilevskaya 1967; Shalganova 1967]. This may be a conservative value due to the lack of relevant acute inhalation toxicity data for workers.


1. ACGIH [1986]. Zirconium. In: Documentation of the threshold limit values and biological exposure indices. 5th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 647.

2. Cochran KW, Doull J, Mazur M, DuBois KP [1950]. Acute toxicity of zirconium, columbium, strontium, lanthanum, cesium, tantalum and yttrium. AMA Arch Ind Hyg Occup Med 1:637-650.

3. Delongeas JL, Burnel D, Netter P, Grignon M, Mur JM, Royer RJ, Grignon G [1983]. Toxicité et pharmacocinétique de l'oxychlorure de zirconium chez la souris et chez le rat. J Pharmacol 14(4):437-447 (in French).

4. Klimmer OR, Doll W [1964]. Zur frage der toxizität und speicherung löslicher zirkoniumverbindungen bei kurz- und langdauernder verfütterung an warmblüter. Arzneimittel-Forschung (Drug Research) 14:1286-1290 (in German).

5. Mogilevskaya OY [1967]. Zirconium. In: Toxicology of the rare metals, ZI Izrael'son, ed. Translated from Russian by Y. Halperin, edited by E. Lieber. Washington, DC: U.S. Atomic Energy Commission and the National Science Foundation, pp. 44-52.

6. NIOSH [1976]. ZH87500. Zirconium nitrate. In: Registry of toxic effects of chemical substances, 1976 ed. Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. 76-191, p. 1230.

7. Shalganova IV [1967]. Hygienic features of the production of rare-metal fluorides. Gig Sanit 32(10-12):343-347 (translated).