PAC Database - Detailed Chemical Data

Chemical Identity
Chemical CAS# UN# Health Code Numbers
Iridium 7439-88-5
11.01
15.01
15.02
Formula Synonyms
Ir
Physical Properties
Mol Wt State MP (°C) BP (°C) VP (Hg) VP (°C) SG LEL (ppm)
192.2 S 4428 21.56
PAC Values
PAC Values (Original Units: mg/m3)
PAC-1 PAC-2 PAC-3
12 130 790
Converted PAC Values (ppm)
PAC-1 PAC-2 PAC-3
1.5 17 100
Technical Basis
A review of available sources identified no exposure limits or acute toxicity data for iridium. Reported GHS health hazard ratings (H319, Category 2), indicating a mid-level health hazard, approximately equivalent to an HHR=2; however, this hazard was in only 22% of the reports. In addition, a recent SDS (2021) reports an NFPA=2. Considering this, analysts assumed and HHR=2 as the TEEL-3 basis. TEEL-2 and TEEL-1 values were derived according to Table 3.5.
• PAC-1 = TEEL-1 = TEEL-2/11
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = HHR=2
This review generated PAC values that are inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a rat oral LD50 not found during this review while the current TEEL-3 basis is an assumed HHR=2, from analysis of GHS and NFPA health hazard statements. The Rev. 29A and current TEEL-2 and TEEL-1 use the same methodology, with differences due to the change in TEEL-3.
References
Chemical information and GHS health hazard codes: https://pubchem.ncbi.nlm.nih.gov/compound/23924
SDS, ThermoFischer (NFPA=2): https://www.fishersci.com/store/msds?partNumber=AC198095000&productDescription=IRIDIUM%2C+POWDER%2C+99.9%25+500MG&vendorId=VN00032119&countryCode=US&language=en
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PAC values marked with a subscript "A" correspond to 60-minute AEGL values.
PAC values marked with a subscript "E" correspond to ERPG values.
PAC values marked by * are >= 10% lower explosive limit (LEL) but < 50% LEL.
PAC values marked by ** are > 50% LEL but < 100% LEL.
PAC values marked by *** are >= LEL.