Agent Name
Alternative Name
Rhodium and compounds
CAS Number
7440-16-6; varies
Rh, varies
Major Category
Rhodium metal; Elemental rhodium; Rhodium compounds; [NIOSH] Rhodium and compounds
Elements, Metallic
Metal: White, hard, ductile, malleable solid with a bluish-gray luster; [NIOSH]
Used in rhodium-platinum alloys for spinnerets; Used in furnace windings, laboratory crucibles, catalysts, and nitric acid manufacturing; Also used in the surfacing of reflectors, electrical contacts, scientific instruments, and jewelry; [ACGIH] Main application is catalytic converter for automobiles to reduce emissions; [Nordberg, p. 1143]
Can cause occupational contact urticaria; [Kanerva, p. 219] "The metals in this group [platinum, palladium, iridium, osmium, rhodium, and ruthenium] generally are nontoxic in the metallic state, but the soluble halide salts (particularly of Pt) and osmium tetroxide are highly reactive. Exposure to these elements results in hypersensitivity allergic reactions in susceptible individuals." [Sullivan, p. 911] Tram drivers in Rome were exposed to Pt, Rh and Pd from catalytic converters at levels about 10 times lower than those known to cause adverse effects in workers. [PMID 18849761] Occupational asthma in a electroplating worker confirmed by bronchoprovocation testing; [Malo]
Biomedical References

Exposure Assessment

Skin Designation (ACGIH)
Insufficient data
1 mg/m3, as Rh (metal and insol. Compds), 0.01 mg/m3, as Rh(sol. Compds)
0.1 mg/m3, as Rh(metal and insol. Compds),0.001 mg/m3, as Rh(sol. Compds)
100 mg/m3, as Rh(metal and insol. Compds), 2 mg/m3, as Rh(sol. Compds)
Excerpts from Documentation for IDLHs
No inhalation toxicity data are available on which to base an IDLH for insoluble rhodium compounds. Therefore, the revised IDLH for insoluble rhodium compounds is 100 mg Rh/m3 based on acute oral toxicity data in animals [Johnson 1981; Veselov 1977]. This may be a conservative value due to the lack of relevant acute toxicity data for workers.

Adverse Effects

ACGIH Carcinogen
Not Classifiable

Diseases, Processes, and Activities Linked to This Agent


Occupational diseases associated with exposure to this agent: