{"data":{"id":"us/40-cfr-766.3","jurisdiction":"us","citation":"40 CFR 766.3","heading":"Definitions.","body":"The definitions in section 3 of TSCA and the definitions of §§ 704.3, 716.3, 717.3, and 790.3 of this chapter also apply to this part.\nCentral Data Exchange or CDX means EPA's centralized electronic submission receiving system.\nChemical Information Submission System or CISS means EPA's electronic, web-based reporting tool for the completion and submission of data, reports, and other information, or its successors.\nCongener means any one particular member of a class of chemical substances. A specific congener is denoted by unique chemical structure, for example 2,3,7,8-tetrachlorodibenzofuran.\nDibenzofuran means any of a family of compounds which has as a nucleus a triple-ring structure consisting of two benzene rings connected through a pair of bridges between the benzene rings. The bridges are a carbon-carbon bridge and a carbon-oxygen-carbon bridge at both substitution positions.\nDibenzo-p-dioxin or dioxin means any of a family of compounds which has as a nucleus a triple-ring structure consisting of two benzene rings connected through a pair of oxygen atoms.\nGuidelines means the Midwest Research Institute (MRI) publication Guidelines for the Determination of Polyhalogenated Dioxins and Dibenzofurans in Commercial Products, EPA contract No. 68-02-3938; MRI Project No. 8201-A(41), 1985.\nHDD or 2,3,7,8-HDD means any of the dibenzo-p-dioxins totally chlorinated or totally brominated at the following positions on the molecular structure: 2,3,7,8; 1,2,3,7,8; 1,2,3,4,7,8; 1,2,3,6,7,8; 1,2,3,7,8,9; and 1,2,3,4,7,8,9.\nHDF or 2,3,7,8-HDF means any of the dibenzofurans totally chlorinated or totally brominated at the following positions on the molecular structure: 2,3,7,8; 1,2,3,7,8; 2,3,4,7,8; 1,2,3,4,7,8; 1,2,3,6,7,8; 1,2,3,7,8,9; 2,3,4,6,7,8; 1,2,3,4,6,7,8; and 1,2,3,4,7,8,9.\nHomolog means a group of isomers that have the same degree of halogenation. For example, the homologous class of tetrachlorodibenzo-p-dioxins consists of all dibenzo-p-dioxins containing four chlorine atoms. When the homologous classes discussed in this part are referred to, the following abbreviations for the prefix denoting the number of halogens are used:\ntetra-, T (4 atoms)\npenta-, Pe (5 atoms)\nhexa-, Hx (6 atoms)\nhepta-, Hp (7 atoms)\nHRGC means high resolution gas chromatography.\nHRMS means high resolution mass spectrometry.\nLevel of quantitation or LOQ means the lowest concentration at which HDDs/HDFs can be reproducibly measured in a specific chemical substance within specified confidence limits, as described in this part.\nPolybrominated dibenzofurans refers to any member of a class of dibenzofurans with two to eight bromine substituents.\nPolybrominated dibenzo-p-dioxin or PBDD means to any member of a class of dibenzo-p-dioxins with two to eight bromine substituents.\nPolychlorinated dibenzofuran means any member of a class of dibenzofurans with two to eight chlorine substituents.\nPolychlorinated dibenzo-p-dioxin or PCDD means any member of a class of dibenzo-p-dioxins with two to eight chlorine substituents.\nPolyhalogenated dibenzofuran or PHDF means any member of a class of dibenzofurans containing two to eight chlorine, bromine, or a combination of chlorine and bromine substituents.\nPolyhalogenated dibenzo-p-dioxin or PHDD means any member of a class of dibenzo-p-dioxins containing two to eight chlorine substituents or two to eight bromine substituents.\nPositive test result means: (1) Any resolvable gas chromatographic peak for any 2,3,7,8-HDD or HDF which exceeds the LOQ listed under § 766.27 for that congener, or (2) exceeds LOQs approved by EPA under § 766.28.\nPrecursor means a chemical substance which is not contaminated due to the process conditions under which it is manufactured, but because of its molecular structure, and under favorable process conditions, it may cause or aid the formation of HDDs/HDFs in other chemicals in which it is used as a feedstock or intermediate.\nQA means quality assurance.\nQC means quality control.\nReimbursement period means the period that begins when the data from the last test to be completed under this part for a specific chemical substance listed in § 766.25 is submitted to EPA, and ends after an amount of time equal to that which had been required to develop that data or 5 years, whichever is later.\nTSCA means the Toxic Substances Control Act, 15 U.S.C. 2601 et seq.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER R—TOXIC SUBSTANCES CONTROL ACT","PART 766—DIBENZO-PARA-DIOXINS/DIBENZOFURANS","Subpart A—General Provisions"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"ff998aa9ad65e0261f167dda43bf1e82215003fb56608cf65fe74ebd42e53793","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-766.2","next":"us/40-cfr-766.5"},"notice":"GroundRules: Original legal text. Not legal advice."}