polychlorinated dibenzofurans polychlorinated dibenzofurans polychlorinated dibenzofurans (pcdfs) are a family of organic compounds with one or several of the hydrogens in the dibenzofuran structure replaced by chlorines. for example, 2,3,7,8-tetrachlorodibenzofuran (tcdf) has chlorine atoms substituted for each of the hydrogens on the number 2, 3, 7, and 8 carbons (see structure in the upper left corner of the second image). polychlorinated dibenzofurans with chlorines at least in positions 2,3,7 and 8 are much more toxic than the parent compound dibenzofurane, with properties and chemical structures similar to polychlorinated dibenzodioxins. these groups together are often inaccurately called dioxins. they are known developmental toxicants, and suspected human carcinogens. pcdfs tend to co-occur with polychlorinated dibenzodioxins (pcdds). pcdfs can be formed by pyrolysis or incineration at temperatures below 1200 °c of chlorine containing products, such as pvc, pcbs, and other organochlorides, or of non-chlorine containing products in the presence of chlorine donors. dibenzofurans are known persistent organic pollutants (pop), classified among the dirty dozen in the stockholm convention on persistent organic pollutants. general chemical structure of pcdfs, where 2 ≤ n+m ≤ 8 structures of the ten 2,3,7,8-substituted pcdf congeners that are toxicologically of most relevance more thorough treatise of all groups with similar actions and binding to aryl hydrocarbon receptor is given in dioxins and dioxin-like compounds. congeners number formula name cas number inchikey pcdf-1 c 12 h 7 clo 1-chlorodibenzofuran 84761-86-4 wrsmjzybniaaee-uhfffaoysa-n pcdf-2 c 12 h 7 clo 2-chlorodibenzofuran 51230-49-0 prktywjfcodjoa-uhfffaoysa-n pcdf-3 c 12 h 7 clo 3-chlorodibenzofuran 25074-67-3 bbozmmaurmevar-uhfffaoysa-n pcdf-4 c 12 h 7 clo 4-chlorodibenzofuran 74992-96-4 rhrybwfahxcucr-uhfffaoysa-n pcdf-12 c 12 h 6 cl 2 o 1,2-dichlorodibenzofuran 64126-85-8 qvaprjwsouitif-uhfffaoysa-n pcdf-13 c 12 h 6 cl 2 o 1,3-dichlorodibenzofuran 94538-00-8 vkibkefgjsprjc-uhfffaoysa-n pcdf-14 c 12 h 6 cl 2 o 1,4-dichlorodibenzofuran 94538-01-9 vhqcmzlphwgudb-uhfffaoysa-n pcdf-16 c 12 h 6 cl 2 o 1,6-dichlorodibenzofuran 74992-97-5 jrsrwaczuflwkf-uhfffaoysa-n pcdf-17 c 12 h 6 cl 2 o 1,7-dichlorodibenzofuran 94538-02-0 xrqnhpgzrfkbjw-uhfffaoysa-n pcdf-18 c 12 h 6 cl 2 o 1,8-dichlorodibenzofuran 81638-37-1 uafnqqbpuwfpgc-uhfffaoysa-n pcdf-19 c 12 h 6 cl 2 o 1,9-dichlorodibenzofuran 70648-14-5 aeksghbvwjhelw-uhfffaoysa-n pcdf-23 c 12 h 6 cl 2 o 2,3-dichlorodibenzofuran 64126-86-9 getjjzzrpqfsfm-uhfffaoysa-n pcdf-24 c 12 h 6 cl 2 o 2,4-dichlorodibenzofuran 24478-74-8 lhtckmyrnoguoa-uhfffaoysa-n pcdf-26 c 12 h 6 cl 2 o 2,6-dichlorodibenzofuran 60390-27-4 xvlcnkfgfhuqnl-uhfffaoysa-n pcdf-27 c 12 h 6 cl 2 o 2,7-dichlorodibenzofuran 74992-98-6 dozutnbcpvumpy-uhfffaoysa-n pcdf-28 c 12 h 6 cl 2 o 2,8-dichlorodibenzofuran 5409-83-6 ivvrjidvyspkfz-uhfffaoysa-n pcdf-34 c 12 h 6 cl 2 o 3,4-dichlorodibenzofuran 94570-83-9 hyqggnwdpqzlgx-uhfffaoysa-n pcdf-36 c 12 h 6 cl 2 o 3,6-dichlorodibenzofuran 74918-40-4 dmobgfaktsxohg-uhfffaoysa-n pcdf-37 c 12 h 6 cl 2 o 3,7-dichlorodibenzofuran 58802-21-4 oltyagnrsnfhlk-uhfffaoysa-n pcdf-46 c 12 h 6 cl 2 o 4,6-dichlorodibenzofuran 64560-13-0 bzfizjnkncjead-uhfffaoysa-n pcdf-123 c 12 h 5 cl 3 o 1,2,3-trichlorodibenzofuran 83636-47-9 ladswaawpmghbe-uhfffaoysa-n pcdf-124 c 12 h 5 cl 3 o 1,2,4-trichlorodibenzofuran 24478-73-7 rqiwkwhvzldxej-uhfffaoysa-n pcdf-126 c 12 h 5 cl 3 o 1,2,6-trichlorodibenzofuran 64560-15-2 cyrzcbuwruackj-uhfffaoysa-n pcdf-127 c 12 h 5 cl 3 o 1,2,7-trichlorodibenzofuran 83704-37-4 afovqgpnozduep-uhfffaoysa-n pcdf-128 c 12 h 5 cl 3 o 1,2,8-trichlorodibenzofuran 83704-34-1 uyigpspcoxgbcs-uhfffaoysa-n pcdf-129 c 12 h 5 cl 3 o 1,2,9-trichlorodibenzofuran 83704-38-5 ictxinqoxpmqpm-uhfffaoysa-n pcdf-134 c 12 h 5 cl 3 o 1,3,4-trichlorodibenzofuran 82911-61-3 fipoitudjfqrrn-uhfffaoysa-n pcdf-136 c 12 h 5 cl 3 o 1,3,6-trichlorodibenzofuran 83704-39-6 agptxrlvbirylv-uhfffaoysa-n pcdf-137 c 12 h 5 cl 3 o 1,3,7-trichlorodibenzofuran 64560-16-3 inrbxogzpdfclq-uhfffaoysa-n pcdf-138 c 12 h 5 cl 3 o 1,3,8-trichlorodibenzofuran 76621-12-0 phfstdoptzheca-uhfffaoysa-n pcdf-139 c 12 h 5 cl 3 o 1,3,9-trichlorodibenzofuran 83704-40-9 sppgdlrokbfnno-uhfffaoysa-n pcdf-146 c 12 h 5 cl 3 o 1,4,6-trichlorodibenzofuran 82911-60-2 xdqrwsujourthk-uhfffaoysa-n pcdf-147 c 12 h 5 cl 3 o 1,4,7-trichlorodibenzofuran 83704-41-0 xtlmvjusianhnd-uhfffaoysa-n pcdf-148 c 12 h 5 cl 3 o 1,4,8-trichlorodibenzofuran 64560-14-1 pcqcydnfbuadok-uhfffaoysa-n pcdf-149 c 12 h 5 cl 3 o 1,4,9-trichlorodibenzofuran 70648-13-4 nvyupbvxkltyhv-uhfffaoysa-n pcdf-167 (pcdf-349) c 12 h 5 cl 3 o 1,6,7-trichlorodibenzofuran 83704-46-5 hewlcncswbmzhg-uhfffaoysa-n pcdf-168 (pcdf-249) c 12 h 5 cl 3 o 1,6,8-trichlorodibenzofuran 82911-59-9 zobvydqwzxujno-uhfffaoysa-n pcdf-178 (pcdf-239) c 12 h 5 cl 3 o 1,7,8-trichlorodibenzofuran 58802-18-9 ynmcxglwhtvmqo-uhfffaoysa-n pcdf-234 c 12 h 5 cl 3 o 2,3,4-trichlorodibenzofuran 57117-34-7 ydladwpbkzodcj-uhfffaoysa-n pcdf-236 c 12 h 5 cl 3 o 2,3,6-trichlorodibenzofuran 57117-33-6 cpmgjtlnrbikqm-uhfffaoysa-n pcdf-237 c 12 h 5 cl 3 o 2,3,7-trichlorodibenzofuran 58802-17-8 ckxmntlggaoerf-uhfffaoysa-n pcdf-238 c 12 h 5 cl 3 o 2,3,8-trichlorodibenzofuran 57117-32-5 nunsnnoyackrik-uhfffaoysa-n pcdf-246 c 12 h 5 cl 3 o 2,4,6-trichlorodibenzofuran 58802-14-5 gtkurbtwzfqhhy-uhfffaoysa-n pcdf-247 c 12 h 5 cl 3 o 2,4,7-trichlorodibenzofuran 83704-42-1 szbzrvjhpzigay-uhfffaoysa-n pcdf-248 c 12 h 5 cl 3 o 2,4,8-trichlorodibenzofuran 54589-71-8 wjurxkwtcomrce-uhfffaoysa-n pcdf-346 c 12 h 5 cl 3 o 3,4,6-trichlorodibenzofuran 83704-43-2 xeuhbcmrixebtd-uhfffaoysa-n pcdf-347 c 12 h 5 cl 3 o 3,4,7-trichlorodibenzofuran 83704-44-3 rpjjbtsxpnfuta-uhfffaoysa-n pcdf-348 c 12 h 5 cl 3 o 3,4,8-trichlorodibenzofuran 83704-45-4 ytzwniqggijhjx-uhfffaoysa-n pcdf-1234 c 12 h 4 cl 4 o 1,2,3,4-tetrachlorodibenzofuran 24478-72-6 aetapifvelridn-uhfffaoysa-n pcdf-1236 c 12 h 4 cl 4 o 1,2,3,6-tetrachlorodibenzofuran 83704-21-6 bbaxflibrpxrbp-uhfffaoysa-n pcdf-1237 c 12 h 4 cl 4 o 1,2,3,7-tetrachlorodibenzofuran 83704-22-7 mdnzfygatdckrb-uhfffaoysa-n pcdf-1238 c 12 h 4 cl 4 o 1,2,3,8-tetrachlorodibenzofuran 62615-08-1 kfqrhgkkshjmco-uhfffaoysa-n pcdf-1239 c 12 h 4 cl 4 o 1,2,3,9-tetrachlorodibenzofuran 83704-23-8 gnqhljhtoattoj-uhfffaoysa-n pcdf-1246 c 12 h 4 cl 4 o 1,2,4,6-tetrachlorodibenzofuran 71998-73-7 nlvwekpjfupvmz-uhfffaoysa-n pcdf-1247 c 12 h 4 cl 4 o 1,2,4,7-tetrachlorodibenzofuran 83719-40-8 mfurkmjldqbhra-uhfffaoysa-n pcdf-1248 c 12 h 4 cl 4 o 1,2,4,8-tetrachlorodibenzofuran 64126-87-0 bftascfrrbhffk-uhfffaoysa-n pcdf-1249 c 12 h 4 cl 4 o 1,2,4,9-tetrachlorodibenzofuran 83704-24-9 zuyytcchkqggov-uhfffaoysa-n pcdf-1267 c 12 h 4 cl 4 o 1,2,6,7-tetrachlorodibenzofuran 83704-25-0 auewyhhkdyuymi-uhfffaoysa-n pcdf-1268 c 12 h 4 cl 4 o 1,2,6,8-tetrachlorodibenzofuran 83710-07-0 kcvgvsibbgijnz-uhfffaoysa-n pcdf-1269 c 12 h 4 cl 4 o 1,2,6,9-tetrachlorodibenzofuran 70648-18-9 iepgllvebkxase-uhfffaoysa-n pcdf-1278 c 12 h 4 cl 4 o 1,2,7,8-tetrachlorodibenzofuran 58802-20-3 jodwpaqnabohdg-uhfffaoysa-n pcdf-1279 c 12 h 4 cl 4 o 1,2,7,9-tetrachlorodibenzofuran 83704-26-1 pdmfrpifzakmlh-uhfffaoysa-n pcdf-1289 c 12 h 4 cl 4 o 1,2,8,9-tetrachlorodibenzofuran 70648-22-5 ohycqukmnphfpt-uhfffaoysa-n pcdf-1346 c 12 h 4 cl 4 o 1,3,4,6-tetrachlorodibenzofuran 83704-27-2 cbbdonkzejkfjp-uhfffaoysa-n pcdf-1347 c 12 h 4 cl 4 o 1,3,4,7-tetrachlorodibenzofuran 70648-16-7 umkcvdztsznwrh-uhfffaoysa-n pcdf-1348 c 12 h 4 cl 4 o 1,3,4,8-tetrachlorodibenzofuran 92341-04-3 xwkrjsmndoxihs-uhfffaoysa-n pcdf-1349 c 12 h 4 cl 4 o 1,3,4,9-tetrachlorodibenzofuran 83704-28-3 pncyjhotzskzpa-uhfffaoysa-n pcdf-1367 c 12 h 4 cl 4 o 1,3,6,7-tetrachlorodibenzofuran 57117-36-9 pitdpgctimcyez-uhfffaoysa-n pcdf-1368 c 12 h 4 cl 4 o 1,3,6,8-tetrachlorodibenzofuran 71998-72-6 bdxkvabzwrzkos-uhfffaoysa-n pcdf-1369 c 12 h 4 cl 4 o 1,3,6,9-tetrachlorodibenzofuran 83690-98-6 njqqzrlwvlwngd-uhfffaoysa-n pcdf-1378 c 12 h 4 cl 4 o 1,3,7,8-tetrachlorodibenzofuran 57117-35-8 csxdvugdfsyxtd-uhfffaoysa-n pcdf-1379 c 12 h 4 cl 4 o 1,3,7,9-tetrachlorodibenzofuran 64560-17-4 iemjmcvyaorwjv-uhfffaoysa-n pcdf-1467 c 12 h 4 cl 4 o 1,4,6,7-tetrachlorodibenzofuran 66794-59-0 rbfnymhniokxla-uhfffaoysa-n pcdf-1468 c 12 h 4 cl 4 o 1,4,6,8-tetrachlorodibenzofuran 82911-58-8 vhobvpnetfrjed-uhfffaoysa-n pcdf-1469 c 12 h 4 cl 4 o 1,4,6,9-tetrachlorodibenzofuran 70648-19-0 jaysbjfhdjomgz-uhfffaoysa-n pcdf-1478 c 12 h 4 cl 4 o 1,4,7,8-tetrachlorodibenzofuran 83704-29-4 ivrdrrwqabcxly-uhfffaoysa-n pcdf-1678 c 12 h 4 cl 4 o 1,6,7,8-tetrachlorodibenzofuran 83704-33-0 kojmoxyetdlopn-uhfffaoysa-n pcdf-2346 c 12 h 4 cl 4 o 2,3,4,6-tetrachlorodibenzofuran 83704-30-7 jnvhshpaamrskk-uhfffaoysa-n pcdf-2347 c 12 h 4 cl 4 o 2,3,4,7-tetrachlorodibenzofuran 83704-31-8 brofyoslfhtgcq-uhfffaoysa-n pcdf-2348 c 12 h 4 cl 4 o 2,3,4,8-tetrachlorodibenzofuran 83704-32-9 iikxrerknijjqy-uhfffaoysa-n pcdf-2367 c 12 h 4 cl 4 o 2,3,6,7-tetrachlorodibenzofuran 57117-39-2 mjcnkmdtlrshnk-uhfffaoysa-n pcdf-2368 c 12 h 4 cl 4 o 2,3,6,8-tetrachlorodibenzofuran 57117-37-0 spmzhwvrmwwtsy-uhfffaoysa-n pcdf-2378 c 12 h 4 cl 4 o 2,3,7,8-tetrachlorodibenzofuran 51207-31-9 ksmvnvhutqzitp-uhfffaoysa-n pcdf-2467 c 12 h 4 cl 4 o 2,4,6,7-tetrachlorodibenzofuran 57117-38-1 nsdxkmrvqosass-uhfffaoysa-n pcdf-2468 c 12 h 4 cl 4 o 2,4,6,8-tetrachlorodibenzofuran 58802-19-0 zspjeacwuwsags-uhfffaoysa-n pcdf-3467 c 12 h 4 cl 4 o 3,4,6,7-tetrachlorodibenzofuran 57117-40-5 lmjlclbsunzlnw-uhfffaoysa-n pcdf-12346 c 12 h 3 cl 5 o 1,2,3,4,6-pentachlorodibenzofuran 83704-47-6 liqjbapsluzutb-uhfffaoysa-n pcdf-12347 c 12 h 3 cl 5 o 1,2,3,4,7-pentachlorodibenzofuran 83704-48-7 dojztbgowiyfac-uhfffaoysa-n pcdf-12348 c 12 h 3 cl 5 o 1,2,3,4,8-pentachlorodibenzofuran 67517-48-0 zctndjsclpjcra-uhfffaoysa-n pcdf-12349 c 12 h 3 cl 5 o 1,2,3,4,9-pentachlorodibenzofuran 83704-49-8 iqsznzvzxofrjs-uhfffaoysa-n pcdf-12367 c 12 h 3 cl 5 o 1,2,3,6,7-pentachlorodibenzofuran 57117-42-7 nzupqbvdiwcpbx-uhfffaoysa-n pcdf-12368 c 12 h 3 cl 5 o 1,2,3,6,8-pentachlorodibenzofuran 83704-51-2 vhqjzofupxezqz-uhfffaoysa-n pcdf-12369 c 12 h 3 cl 5 o 1,2,3,6,9-pentachlorodibenzofuran 83704-52-3 ipsfqakxdjvqox-uhfffaoysa-n pcdf-12378 c 12 h 3 cl 5 o 1,2,3,7,8-pentachlorodibenzofuran 57117-41-6 sbmivuvrfpgoeb-uhfffaoysa-n pcdf-12379 c 12 h 3 cl 5 o 1,2,3,7,9-pentachlorodibenzofuran 83704-53-4 jvuseqpowcbyng-uhfffaoysa-n pcdf-12389 c 12 h 3 cl 5 o 1,2,3,8,9-pentachlorodibenzofuran 83704-54-5 nkglwujpctudeh-uhfffaoysa-n pcdf-12467 c 12 h 3 cl 5 o 1,2,4,6,7-pentachlorodibenzofuran 83704-50-1 bqtcodovgxjhrb-uhfffaoysa-n pcdf-12468 c 12 h 3 cl 5 o 1,2,4,6,8-pentachlorodibenzofuran 69698-57-3 jdtuaypjssxdno-uhfffaoysa-n pcdf-12469 c 12 h 3 cl 5 o 1,2,4,6,9-pentachlorodibenzofuran 70648-24-7 qdqfgvxgpsyeju-uhfffaoysa-n pcdf-12478 c 12 h 3 cl 5 o 1,2,4,7,8-pentachlorodibenzofuran 58802-15-6 gcfdwhikrxcupj-uhfffaoysa-n pcdf-12479 c 12 h 3 cl 5 o 1,2,4,7,9-pentachlorodibenzofuran 71998-74-8 iygvhnhworpmfu-uhfffaoysa-n pcdf-12489 c 12 h 3 cl 5 o 1,2,4,8,9-pentachlorodibenzofuran 70648-23-6 zspapwgnagtcca-uhfffaoysa-n pcdf-12678 (pcdf-23489) c 12 h 3 cl 5 o 1,2,6,7,8-pentachlorodibenzofuran 69433-00-7 zaavdgljeoxcmv-uhfffaoysa-n pcdf-12679 c 12 h 3 cl 5 o 1,2,6,7,9-pentachlorodibenzofuran 70872-82-1 qqrrqevosmevqb-uhfffaoysa-n pcdf-13467 c 12 h 3 cl 5 o 1,3,4,6,7-pentachlorodibenzofuran 83704-36-3 jvyyduwjijmogw-uhfffaoysa-n pcdf-13468 c 12 h 3 cl 5 o 1,3,4,6,8-pentachlorodibenzofuran 83704-55-6 cokiayprhyhych-uhfffaoysa-n pcdf-13469 c 12 h 3 cl 5 o 1,3,4,6,9-pentachlorodibenzofuran 70648-15-6 mysafuyqsbeedr-uhfffaoysa-n pcdf-13478 c 12 h 3 cl 5 o 1,3,4,7,8-pentachlorodibenzofuran 58802-16-7 orsuqgvcwlxklz-uhfffaoysa-n pcdf-13479 c 12 h 3 cl 5 o 1,3,4,7,9-pentachlorodibenzofuran 70648-20-3 gfxplabvzobccw-uhfffaoysa-n pcdf-13678 c 12 h 3 cl 5 o 1,3,6,7,8-pentachlorodibenzofuran 70648-21-4 frlmqduyujihcz-uhfffaoysa-n pcdf-14678 c 12 h 3 cl 5 o 1,4,6,7,8-pentachlorodibenzofuran 83704-35-2 vanghzrykxdprr-uhfffaoysa-n pcdf-23467 c 12 h 3 cl 5 o 2,3,4,6,7-pentachlorodibenzofuran 57117-43-8 sjfbzrqkgoghev-uhfffaoysa-n pcdf-23468 c 12 h 3 cl 5 o 2,3,4,6,8-pentachlorodibenzofuran 67481-22-5 mkrforpsrbmaip-uhfffaoysa-n pcdf-23478 c 12 h 3 cl 5 o 2,3,4,7,8-pentachlorodibenzofuran 57117-31-4 ogbqilnblmppdp-uhfffaoysa-n pcdf-123467 c 12 h 2 cl 6 o 1,2,3,4,6,7-hexachlorodibenzofuran 79060-60-9 snwfmkxfmvhbkd-uhfffaoysa-n pcdf-123468 c 12 h 2 cl 6 o 1,2,3,4,6,8-hexachlorodibenzofuran 69698-60-8 ucfgnwhervqwmz-uhfffaoysa-n pcdf-123469 c 12 h 2 cl 6 o 1,2,3,4,6,9-hexachlorodibenzofuran 91538-83-9 kffuzirojgxtqh-uhfffaoysa-n pcdf-123478 c 12 h 2 cl 6 o 1,2,3,4,7,8-hexachlorodibenzofuran 70648-26-9 lvybaqivpkcoee-uhfffaoysa-n pcdf-123479 c 12 h 2 cl 6 o 1,2,3,4,7,9-hexachlorodibenzofuran 91538-84-0 bkixwrbzcqezaq-uhfffaoysa-n pcdf-123489 c 12 h 2 cl 6 o 1,2,3,4,8,9-hexachlorodibenzofuran 92341-07-6 vsduqubujrnreh-uhfffaoysa-n pcdf-123678 c 12 h 2 cl 6 o 1,2,3,6,7,8-hexachlorodibenzofuran 57117-44-9 jeyjjjxofwnehn-uhfffaoysa-n pcdf-123679 c 12 h 2 cl 6 o 1,2,3,6,7,9-hexachlorodibenzofuran 92341-06-5 jzvolxqrejnttl-uhfffaoysa-n pcdf-123689 c 12 h 2 cl 6 o 1,2,3,6,8,9-hexachlorodibenzofuran 75198-38-8 wlgqzuohextwfh-uhfffaoysa-n pcdf-123789 c 12 h 2 cl 6 o 1,2,3,7,8,9-hexachlorodibenzofuran 72918-21-9 pyusjfjvdvsxiu-uhfffaoysa-n pcdf-124678 c 12 h 2 cl 6 o 1,2,4,6,7,8-hexachlorodibenzofuran 67562-40-7 ckddygbbkxihry-uhfffaoysa-n pcdf-124679 c 12 h 2 cl 6 o 1,2,4,6,7,9-hexachlorodibenzofuran 75627-02-0 fahipphrjjjqog-uhfffaoysa-n pcdf-124689 c 12 h 2 cl 6 o 1,2,4,6,8,9-hexachlorodibenzofuran 69698-59-5 fgzcxipkucjghw-uhfffaoysa-n pcdf-134678 c 12 h 2 cl 6 o 1,3,4,6,7,8-hexachlorodibenzofuran 71998-75-9 ogtzincgzyxzcr-uhfffaoysa-n pcdf-134679 c 12 h 2 cl 6 o 1,3,4,6,7,9-hexachlorodibenzofuran 92341-05-4 turxxoifvabbpw-uhfffaoysa-n pcdf-234678 c 12 h 2 cl 6 o 2,3,4,6,7,8-hexachlorodibenzofuran 60851-34-5 xtahlacqovxinq-uhfffaoysa-n pcdf-1234678 c 12 hcl 7 o 1,2,3,4,6,7,8-heptachlorodibenzofuran 67562-39-4 wdmkcpivjoghbf-uhfffaoysa-n pcdf-1234679 c 12 hcl 7 o 1,2,3,4,6,7,9-heptachlorodibenzofuran 70648-25-8 jwxwoeukhxousk-uhfffaoysa-n pcdf-1234689 c 12 hcl 7 o 1,2,3,4,6,8,9-heptachlorodibenzofuran 69698-58-4 badfhcolisgrrw-uhfffaoysa-n pcdf-1234789 c 12 hcl 7 o 1,2,3,4,7,8,9-heptachlorodibenzofuran 55673-89-7 vezctzwljywarh-uhfffaoysa-n pcdf-12346789 c 12 cl 8 o octachlorodibenzofuran 39001-02-0 rhirofaguqoflu-uhfffaoysa-n safety, toxicity, regulation occupational exposure to pcdfs may occur through inhalation and contact with the skin, although intake even in workers at waste incineration plants are not particularly high. for general population the most important source is food of animal origin like with other dioxin-like compounds. the most relevant congener is 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-pcdf) which is more toxic and based on relative toxicity more prevalent than other pcdfs.