Rhodium (soluble compounds, as Rh)

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

CAS number: Varies

NIOSH REL: 0.001 mg/m3 TWA

Current OSHA PEL: 0.001 mg/m3 TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.01 mg/m3 TWA

Description of substance Varies

Original (SCP) IDLH*: No evidence [*Note: “Effective” IDLH = 2 mg Rh/m3 — see discussion below.]

Basis for original (SCP) IDLH: There is no indication from experimental data or industrial experience that the soluble compounds of rhodium produce toxic effects in man. Therefore, because no evidence of an IDLH exists, respirators have been selected on the basis of the assigned protection factor afforded by each device up to 2,000 ´ the OSHA PEL of 0.001 mg Rh/m3 (i.e., 2 mg Rh/m3); only the “most protective” respirators are permitted for use in concentrations exceeding 2 mg Rh/m3.

Short-term exposure guidelines: None developed


Animal or human data: None relevant for use in determining the revised IDLH.

Page last reviewed: December 4, 2014