Zirconium compounds (as Zr)

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

ACUTE TOXICITY DATA:

Lethal concentration data:

Species	Reference	LC50	LCLo	Time	Adjusted 0.5-hr LC (CF)	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 (mg/kg)	LDLo (mg/kg)	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.

REFERENCES:

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).

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