PAC Database - Detailed Chemical Data
Chemical Identity
| Chemical | CAS# | UN# | Health Code Numbers | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Methylenebis(isocyanato-benzene), 1,1'-; (Diphenyl methane diisocyanate) | 26447-40-5 |
4.00
3.00
|
||||||||||
| Formula | Synonyms | |||||||||||
| C15.H10.N2.O | ||||||||||||
Physical Properties
| Mol Wt | State | MP (°C) | BP (°C) | VP (Hg) | VP (°C) | SG | LEL (ppm) |
|---|---|---|---|---|---|---|---|
| 250.26 |
PAC Values
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 0.090 | 5.0 | 55 |
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 0.0088 | 0.49 | 5.4 |
Technical Basis
A review of available sources identified exposure limits (OEL-STELs and TWAs) for this chemical. In addition, because 1,1’-methylenebis(isocyanato-benzene) is an isomer of 4,4'-diphenylmethane diisocyanate (MDI, CASRN: 101-68-8) analysts also evaluated available exposure limits (ERPGs, TWAs) and acute toxicity data for MDI (Section 3.4.6). 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. Inhalation exposures were scaled to 60-minute equivalents using the ten Berge equation (Section 3.3.4). The ERPG-3 and ERPG-2 for MDI were selected due to their priority among Protective Action Criteria (Section 1, Section 3.4.6). The OEL-STEL (Poland, 15-minute) was selected as the TEEL-1.
• PAC-1 = TEEL-1 = OEL-STEL (Poland)
• PAC-2 = TEEL-2 = ERPG-2 (Methylene bisphenyl isocyanate (MDI); CASRN: 101-68-8; 5 mg/m3)
• PAC-3 = TEEL-3 = ERPG-3 (Methylene bisphenyl isocyanate (MDI); CASRN: 101-68-8; 55 mg/m3)
This review generated PAC values that are inconsistent with Rev. 29A. The Rev. 29A TEEL-3 was a weight adjusted 1990 cyanide IDLH, while the current TEEL-3 is an ERPG-3 for structurally similar chemical, 4,4'-diphenylmethane diisocyanate (MDI, CASRN: 101-68-8). The Rev. 29A TEEL-2 was derived from the TEEL-3, while the current TEEL-3 is an ERPG-2 for structurally similar chemical (MDI, CASRN: 101-68-8). The Rev. 29A TEEL-1 basis was a weight adjusted MAK-TWA for cyanides, while the current TEEL-1 is an exposure limit (OEL-STEL, see note Table 3.5).
• PAC-1 = TEEL-1 = OEL-STEL (Poland)
• PAC-2 = TEEL-2 = ERPG-2 (Methylene bisphenyl isocyanate (MDI); CASRN: 101-68-8; 5 mg/m3)
• PAC-3 = TEEL-3 = ERPG-3 (Methylene bisphenyl isocyanate (MDI); CASRN: 101-68-8; 55 mg/m3)
This review generated PAC values that are inconsistent with Rev. 29A. The Rev. 29A TEEL-3 was a weight adjusted 1990 cyanide IDLH, while the current TEEL-3 is an ERPG-3 for structurally similar chemical, 4,4'-diphenylmethane diisocyanate (MDI, CASRN: 101-68-8). The Rev. 29A TEEL-2 was derived from the TEEL-3, while the current TEEL-3 is an ERPG-2 for structurally similar chemical (MDI, CASRN: 101-68-8). The Rev. 29A TEEL-1 basis was a weight adjusted MAK-TWA for cyanides, while the current TEEL-1 is an exposure limit (OEL-STEL, see note Table 3.5).
References
Chemical information: https://comptox.epa.gov/dashboard/chemical/details/DTXSID3027900
OELs: https://ilv.ifa.dguv.de/limitvalues/24167
MDI chemical information: https://pubchem.ncbi.nlm.nih.gov/compound/7570
MDI (CASRN: 101-68-8) exposure limits: https://www.osha.gov/chemicaldata/23