Toxic Equivalency Factors

Table 12 to Subpart DDDD of Part 63—Toxic Equivalency Factors Dioxin/furan congener Toxic equivalency factor 2,3,7,8-tetrachlorinated dibenzo-p-dioxin 1 1,2,3,7,8-pentachlorinated dibenzo-p-dioxin 1 1,2,3,4,7,8-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,7,8,9-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,6,7,8-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,4,6,7,8-heptachlorinated dibenzo-p-dioxin 0.01 octachlorinated dibenzo-p-dioxin 0.0003 2,3,7,8-tetrachlorinated dibenzofuran 0.1 2,3,4,7,8-pentachlorinated dibenzofuran 0.3 1,2,3,7,8-pentachlorinated dibenzofuran 0.03 1,2,3,4,7,8-hexachlorinated dibenzofuran 0.1 1,2,3,6,7,8-hexachlorinated dibenzofuran 0.1 1,2,3,7,8,9-hexachlorinated dibenzofuran 0.1 2,3,4,6,7,8-hexachlorinated dibenzofuran 0.1 1,2,3,4,6,7,8-heptachlorinated dibenzofuran 0.01 1,2,3,4,7,8,9-heptachlorinated dibenzofuran 0.01 octachlorinated dibenzofuran 0.0003 [91 FR 41463, July 6, 2026]