PAC Database - Detailed Chemical Data
Chemical Identity
| Chemical | CAS# | UN# | Health Code Numbers | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Methyl mercury | 22967-92-6 |
15.02
4.05
4.09
3.05
7.10
7.11
3.02
3.09
3.01
2.00
|
||||||||||
| Formula | Synonyms | |||||||||||
| CH3Hg | ||||||||||||
Physical Properties
| Mol Wt | State | MP (°C) | BP (°C) | VP (Hg) | VP (°C) | SG | LEL (ppm) |
|---|---|---|---|---|---|---|---|
| 215.63 | S |
PAC Values
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 0.0037 | 0.25 | 0.50 |
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 0.033 | 2.2 | 4.4 |
Technical Basis
A review of available sources identified mouse and rat acute toxicity data (LD50) for intraperitoneal and oral routes. In addition, there are exposure limits for mercury (organo) alkyl compounds (mercury alkyl, CASRN: 7439-97-6; ceiling limits, STELs, TWAs, ERPG-3/ERPG-2, and IDLH;). Data sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were selected according to type of exposure, species, and route according to the hierarchies stated in Sections 3.3.1, 3.3.2, and evaluated using factors in Tables 3.2, 3.3, and 3.4. The mercury (organo) alkyl compounds ERPG-3 and ERPG-2 were selected as the TEEL-3 and TEEL-2, respectively. Note that the methyl mercury toxicity doses evaluated resulted in TEEL values comparable in magnitude to these exposure limits. The mercury TLV-STEL was selected as the TEEL-1 basis and a compound adjustment factor was applied (Section 3.2.2).
• TEEL-1 = MW-adjusted TLV-STEL (mercury (organo) alkyl compounds as Hg, CASRN: 7439-97-6, 0.03 mg/m3)
• TEEL-2 = ERPG-2 (mercury (organo) alkyl compounds as Hg, CASRN: 7439-97-6, 0.25 ppm)
• TEEL-3 = ERPG-3 (mercury (organo) alkyl compounds as Hg, CASRN: 7439-97-6, 0.5 ppm)
This review generated TEEL-3 and TEEL-2 values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was the alkyl mercury 1994 IDLH (CASRN: 7439-97-6) and the Rev. 29A TEEL-2 basis was a mercury PEL-C; compound adjustment factors were applied to both limits. The current TEEL-3 and TEEL-2 are unadjusted ERPGs for mercury (organo) alkyl compounds (CASRN: 7439-97-6), a higher priority source (Section 1). The Rev. 29A and current TEEL-1 values, methodology, and source are consistent.
• TEEL-1 = MW-adjusted TLV-STEL (mercury (organo) alkyl compounds as Hg, CASRN: 7439-97-6, 0.03 mg/m3)
• TEEL-2 = ERPG-2 (mercury (organo) alkyl compounds as Hg, CASRN: 7439-97-6, 0.25 ppm)
• TEEL-3 = ERPG-3 (mercury (organo) alkyl compounds as Hg, CASRN: 7439-97-6, 0.5 ppm)
This review generated TEEL-3 and TEEL-2 values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was the alkyl mercury 1994 IDLH (CASRN: 7439-97-6) and the Rev. 29A TEEL-2 basis was a mercury PEL-C; compound adjustment factors were applied to both limits. The current TEEL-3 and TEEL-2 are unadjusted ERPGs for mercury (organo) alkyl compounds (CASRN: 7439-97-6), a higher priority source (Section 1). The Rev. 29A and current TEEL-1 values, methodology, and source are consistent.
References
Chemical information: https://pubchem.ncbi.nlm.nih.gov/compound/Methylmercury-II
Mercury (organo) alkyl compounds, as Hg exposure limits: https://www.osha.gov/chemicaldata/503
Mercury (organo) alkyl compounds, as Hg IDLH: https://www.cdc.gov/niosh/idlh/merc-hg.html