Regulations last checked for updates: Feb 21, 2025

Title 40 - Protection of Environment last revised: Nov 21, 2025
Appendix - Table 5 to Subpart FFFFF of Part 63—Toxic Equivalency Factors

As stated in § 63.7825(u), you must demonstrate compliance with each dioxin/furan emission limit that applies to you by calculating the sum of the 2,3,7,8-TCDD TEQs using the 2005 World Health Organization (WHO) toxicity equivalence factors (TEF) presented in the following table:

For each dioxin/furan congener . . . You must calculate its
2,3,7,8-TCDD
TEQ using the following TEF . . .
2,3,7,8-tetrachlorodibenzo-p-dioxin1
1,2,3,7,8-pentachlorodibenzo-p-dioxin1
1,2,3,4,7,8-hexachlorodibenzo-p-dioxin0.1
1,2,3,7,8,9-hexachlorodibenzo-p-dioxin0.1
1,2,3,6,7,8-hexachlorodibenzo-p-dioxin0.1
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin0.01
Octachlorodibenzo-p-dioxin0.0003
2,3,7,8-tetrachlorodibenzofuran0.1
1,2,3,7,8-pentachlorodibenzofuran0.03
2,3,4,7,8-pentachlorodibenzofuran0.3
1,2,3,4,7,8-hexachlorodibenzofuran0.1
1,2,3,6,7,8-hexachlorodibenzofuran0.1
1,2,3,7,8,9-hexachlorodibenzofuran0.1
2,3,4,6,7,8-hexachlorodibenzofuran0.1
1,2,3,4,6,7,8-heptachlorodibenzofuran0.01
1,2,3,4,7,8,9-heptachlorodibenzofuran0.01
Octachlorodibenzofuran0.0003
[89 FR 23335, Apr. 3, 2024]
authority: 42 U.S.C. 7401
source: 57 FR 61992, Dec. 29, 1992, unless otherwise noted.