PAC Database - Detailed Chemical Data

Chemical Identity
Chemical CAS# UN# Health Code Numbers
Pentachlorodibenzofuran, 1,2,3,7,8- 57117-41-6

Formula Synonyms
Physical Properties
Mol Wt State MP (°C) BP (°C) VP (Hg) VP (°C) SG LEL (ppm)
340.4 S
PAC Values
PAC Values (Original Units: mg/m3)
0.0043 0.047 0.28
Converted PAC Values (ppm)
0.00031 0.0034 0.020
Technical Basis
A review of available sources identified that 1,2,3,7,8-PentaCDF is classified as a dioxin-like compound (DLC). Since the late 1980s, the Environmental Protection Agency (EPA) has implemented a Toxicity Equivalency Factor (TEF) to evaluate the acute toxicity of dioxin and DLCs relative to a reference chemical (2,3,7,8-tetrachlorodibenzo-p-dioxin, CASRN: 1746-01-6), which can be applied to scale these chemicals according to the following equation:
〖TEEL〗_(dioxin or DLC)=〖TEEL〗_(2,3,7,8-TCDD)/〖TEF〗_(dioxin or DLC)
The TEF for 1,2,3,7,8-PentaCDF is 0.03. Use of this non-standard TEEL derivation requires additional review and approval according to Sections 4.2 and 4.3, recorded in a deviation memo.
TEEL-1 = TEEL-12,3,7,8-TCDD/ TEF
TEEL-2 = TEEL-22,3,7,8-TCDD/ TEF
TEEL-3 = TEEL-32,3,7,8-TCDD/ TEF
This review generated TEEL values consistent with those in Rev. 29A. The Rev. 29A and current TEEL-2 were developed from the same source and methodology, therefore minor differences in values may be due to rounding.
2,3,7,8-TCDD TEELs, available at
Agency for Toxic Substances and Disease Registry. 2022. "ATSDR Office of Community Health Hazard Assessment Toxic Equivalents Guidance for Dioxin and Dioxin-like Compounds." Toxic Equivalents Guidance for Dioxin and Dioxin-like Compounds, April 15: 1-28. Accessed July 17, 2023. .
U.S. Environmental Protection Agency. 2023. Dioxin and Dioxin-Like Compounds Toxic Equivalency Information. March 11. Accessed 1 12, 2024.
U.S. Environmental Protection Agency. 2010. "Recommended Toxicity Equivalence Factors (TEFs) for Human Health Risk Assessments of 2,3,7,8-Tetrachlorodibenzo-p-dioxin and Dioxin-Like Compounds." Risk Assessment Forum. Washington, DC. Accessed July 17, 2023.
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