Chlorine Industry Questions & Answers for Reporting
Dioxin and Dioxin-Like Compounds Under EPCRA 313

The Chlorine Chemistry Division of the American Chemistry Council prepared this document to briefly answer a number of common questions on Toxics Release Inventory (TRI) reporting requirements for dioxin and dioxin-like compounds.  For more detailed information, see EPA’s Guidance for Reporting Toxic Chemicals within the Dioxin and Dioxin-like Compounds Category (December 2000).  EPA’s reporting guidance is available on the Agency’s website at

What is the reporting threshold for the dioxin and dioxin-like compound category?

The reporting threshold for the dioxin category is 0.1 gram total mass of all 7 dioxin and 10 furan congeners in the dioxin and dioxin-like compounds category. 

What level of reporting precision is required?

Once the threshold is met, facilities should report emissions at the level of precision supported by the underlying data and the estimation techniques on which the estimate is based.  However, the smallest quantity that should be reported on Form R is 0.0001 gram (100 microgram).  If the amount is 0.00005 microgram or less, zero can be entered.  If the amount is between 0.00005 and 0.0001 gram, then you can enter either 0.0001 gram or the actual number.

How will dioxin data be reported?

EPA will require reporting of the total mass of all 17 dioxin and furan congeners.  Data will not be reported on a Toxic Equivalent (TEQ) basis.

If you have information on the distribution of the congeners for your facility, you must report:

  • either the distribution that best represents the distribution of the total quantity of dioxin and dioxin-like compounds released to all media from the facility;
  • or its one best media-specific distribution. 

To report this distribution, you will provide a percentage for each of the 17 compounds.

Do the de minimis exemption, Form A reporting, and range reporting apply to the dioxin and dioxin like compounds category?

No.  The de minimis exemption will not be applicable to the dioxins category or to other PBTs, except for purposes of the supplier notification requirement.  EPA has also excluded PBTs from the "TRI Alternate Threshold for Facilities with Low Annual Reportable Amounts."  Therefore submitting a Form A rather than a Form R is not an option for these chemicals.  In addition, no ranges can be used for reporting PBTs. 

What activities are covered by the qualifier for the dioxin and dioxin-like compounds category?

The final rule has the following activity qualifier for the dioxin category:

  • Manufacturing; and the processing or otherwise use of dioxin and dioxin-like compounds if the dioxin and dioxin-like compounds are present as contaminants in a chemical and if they were created during the manufacturing of that chemical.

All dioxin and dioxin-like compounds manufactured by your facility must be applied towards the 0.1 gram manufacturing threshold and included in release and other waste management calculations.  "Manufacture" includes coincidental production during any process, as well as importation.

Under the activity qualifier, a facility must account for dioxins present as contaminants in a chemical that is processed or otherwise used, but only if the dioxins were created during the manufacturing of that chemical. 

What reporting requirements will be passed on to downstream customers?

If your customers are covered under EPCRA 313, they may have to account for dioxins present as contaminants in your products.  According to EPA’s reporting guidance, if you make chemical A and incidentally manufacture dioxins as contaminants in that chemical, then customers that process or otherwise use chemical A would have to include these dioxins in their threshold determinations as well as in release and other waste management calculations.  However, if a customer then uses chemical A to make chemical B and chemical B contains dioxins merely because they were in chemical A, a facility using or processing chemical B would not have to report the dioxins in chemical B.

What chemicals are identified in the guidance as potentially containing by-product dioxins?

EPA’s reporting guidance identifies several chemicals as having the potential to contain dioxins created as byproducts during the manufacturing process for those chemicals.  The list includes ethylene dichloride manufactured by oxychlorination.  In response to public comments, EPA removed vinyl chloride and PVC from the original draft list. 

Chlorine and sodium hydroxide are not listed.  Nevertheless, reporting requirements apply to dioxin created during the manufacturing process of any chemical, whether listed in the guidance or not.

How will facilities estimate releases?

EPA describes 3 different approaches for estimating releases:

  • Facility-specific actual monitoring data,
  • Facility-specific emission factors (based on specific monitoring data from a similar facility)
  • EPA’s default emission factors for those industrial sectors listed in the guidance. 

In general, EPA considers these three approaches to be hierarchical.  However, the facility operator is encouraged to exercise "best engineering judgment" when selecting the appropriate approach.  When documenting the annual releases and other waste management quantities, EPA recommends that you indicate which approach was used in deriving the estimate.

What emission factors are provided?

EPA’s reporting guidance provides facility-specific emission factors for a number of source categories.  Of particular interest to the chlorine industry are emission factors for 1) hazardous waste combustion facilities and 2) commercial boilers and industrial furnaces that burn hazardous waste as an auxiliary fuel. The guidance does not provide emission factors for chlor-alkali manufacture or other chlorine industry processes.

How should facilities treat "non-detects" of dioxins?

According to EPA’s reporting guidance, monitoring data and emission factors determined for your facility should be reported "in a manner consistent with the methods and procedures that EPA has developed for determining if these compounds are present in various industrial processes."  If the method treats non-detects as zero (e.g., Method 1613, Method 23), then they should be reported as zero.  However, if a facility has better information than is provided by these methods, that information should be used.

EPA’s reporting guidance states that if the method being used by a facility to detect dioxins is not an EPA approved method and the detection level being used is not as sensitive as those approved for use under EPA methods, then the facility must use "reasonable judgment" as to the presence and amount of a listed toxic chemical, based on the best readily available information.  If the reportable toxic chemical is known to be present, a concentration equivalent to half the detection limit should be used.

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