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Silver (metal dust and soluble compounds, as Ag)

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

CAS number: 7440–22–4 (Metal)

NIOSH REL: 0.01 mg/m3 TWA

Current OSHA PEL: 0.01 mg/m3 TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: Metal: 0.1 mg/m3 TWA;

Soluble compounds: 0.01 mg/m3 TWA

Description of substance: Varies

Original (SCP) IDLH*: No Evidence [*Note: “Effective” IDLH = 20 mg Ag/m3 — see discussion below.]

Basis for original (SCP) IDLH: The available toxicological data contain no evidence that an acute exposure by inhalation to silver metal or the soluble compounds of silver could impede escape. For this draft technical standard, therefore, respirators have been selected on the basis of the assigned protection factor afforded by each device up to 2,000 ´ the OSHA PEL of 0.01 mg Ag/m3 (i.e., 20 mg Ag/m3); only the “most protective” respirators are permitted for use in concentrations exceeding 20 mg Ag/m3.

Short-term exposure guidelines: None developed


Lethal dose data:

Species Reference Route LD50(mg/kg) LDLo(mg/kg) Adjusted LD Derived value
AgNO3 Rabbit Flury & Zernik 1935 oral —– 800 3,556 mg Ag/m3 356 mg Ag/m3
AgNO3 Dog Flury & Zernik 1935 oral —– 20 89 mg Ag/m3 8.9 mg Ag/m3
Ag2O Smyth et al. 1969 oral 2,820 —– 18,385 mg Ag/m3 1,839 mg Ag/m3

Human data: It has been reported that 29 mg/kg is the probable lethal dose [Arena 1970]. [Note: A dose of 29 mg/kg is equivalent to a 70-kg worker being exposed to 135 mg/m3 for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.]

Revised IDLH: 10 mg Ag/m3Basis for revised IDLH: No inhalation toxicity data are available on which to base an IDLH for silver (metal dust and soluble compounds). Therefore, the revised IDLH for silver (metal dust and soluble compounds) is 10 mg Ag/m3 based on acute oral toxicity data in humans [Arena 1970] and animals [Flury and Zernik 1935].


1. Arena JM [1970]. Poisoning; toxicology, symptoms, treatments. 2nd ed. Springfield, IL: C.C. Thomas, 2:73.

2. Flury F, Zernik F [1935]. Zusammenstellung der toxischen und letalen dosen für die gebräuchlichsten gifte und versuchstiere. Abder Hand Biol Arbeitsmethod 4:1289-1422 (in German).

3. Smyth HF Jr, Carpenter CP, Weil CS, Pozzani UC, Striegel JA, Nycum JS [1969]. Range-finding toxicity data: list VII. Am Ind Hyg Assoc J 30(5):470-476.