PAC Database - Detailed Chemical Data

Chemical Identity
Chemical CAS# UN# Health Code Numbers
Thallium oxide; (Thallous oxide) 1314-12-1
15.01
11.01
15.02
4.08
4.05
7.01
7.00
4.09
4.06
4.10
Formula Synonyms
OTl2
Physical Properties
Mol Wt State MP (°C) BP (°C) VP (Hg) VP (°C) SG LEL (ppm)
424.77 S 579 9.52
PAC Values
PAC Values (Original Units: mg/m3)
PAC-1 PAC-2 PAC-3
0.062 3.5 21
Converted PAC Values (ppm)
PAC-1 PAC-2 PAC-3
0.0036 0.20 1.2
Technical Basis
A review of limited sources identified exposure limits (TLV-TWA, IDLH) for soluble thallium compounds. Data sources were selected according to the hierarchy listed in Table 3.1. Thallium(I) oxide hydrolyzes to thallium hydroxide (TlOH) in atmospheric conditions and was therefore evaluated as a soluble thallium compound. The IDLH (1990) was selected as the TEEL-3 basis and the TLV-TWA as the TEEL-1 basis; a compound adjustment factor was applied to these exposure limits (Section 3.2.2). The TEEL-2 value was derived according to Table 3.5.
• TEEL-1 = MW-adjusted TLV-TWA (soluble thallium, CASRN: 7440-28-0, 0.2 mg/m3) x 3
• TEEL-2 = TEEL-3/6
• TEEL-3 = MW-adjusted IDLH (1990, soluble thallium, CASRN: 7440-28-0, 20 mg/m3)
This review generated TEEL values consistent with Rev. 29A.
References
IDLH (1990) for soluble Thallium. Retrieved from: https://www.cdc.gov/niosh/idlh/thallium.html
TLV-TWA, 2009. Retrieved from: https://www.osha.gov/chemicaldata/521
https://pubchem.ncbi.nlm.nih.gov/compound/Dithallium-oxide
Availability of Tl compounds, with discussion of Tl2O environmental fate in air (pgs. iv, 7) and physical properties (Table 1-1). Retrieved from: https://nepis.epa.gov/Exe/ZyPDF.cgi/9100RH6Z.PDF?Dockey=9100RH6Z.PDF
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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.