UNITED NATIONS SC UNEP/POPS/POPRC.12/INF/12 Distr.: General 25 July 2016 English only Stockholm Convention on Persistent Organic Pollutants Persistent Organic Pollutants Review Committee Twelfth meeting Rome, 1923 September 2016 Item 4 (c) (ii) of the provisional agenda* Technical work: consideration of recommendations to the Conference of the Parties: unintentional releases of hexachlorobutadiene Draft evaluation of new information in relation to listing of hexachlorobutadiene in Annex C to the Stockholm Convention Note by the Secretariat As referred to in the note by the Secretariat on new information in relation to the listing of hexachlorobutadiene in Annex C to the Stockholm Convention (UNEP/POPS/POPRC.12/6), the annex to the present note sets out the draft evaluation of new information in relation to listing of hexachlorobutadiene in Annex C to the Stockholm Convention. The present note, including its annex, has not been formally edited. * UNEP/POPS/POPRC.12/1. 250716 UNEP/POPS/POPRC.12/INF/12 Annex Draft evaluation of new information in relation to the listing of hexachlorobutadiene in Annex C of the Stockholm Convention June 2016 2 UNEP/POPS/POPRC.12/INF/12 Table of Contents Executive summary .................................................................................................................................... 4 1. Introduction ..................................................................................................................................... 6 1.1 Overview ............................................................................................................................. 6 1.2 Background to hexachlorobutadiene .................................................................................. 7 1.3 Aims of the evaluation ........................................................................................................ 8 2. Assessment of new information (since development of the draft risk management evaluation) . 8 2.1 Review of information provided by parties and observers ................................................ 8 2.1.1 Introduction to review of information provided ................................................................. 8 2.1.2 Sources of unintentional formation, releases and emissions of hexachlorobutadiene identified in the risk management evaluation for the chemical as well as new sources ... 8 2.1.4 Alternative processes for the production of halogenated chemicals to reduce and elimate the unintentional production of hexachlorobutadiene ...................................................... 10 2.1.5 Substitution of chlorinated chemicals identified as a source of unintentional releases of hexachlorobutadiene ......................................................................................................... 10 2.1.6 Cost of measures implemented to reduce and/or eliminate unintentional releases of hexachlorobutadiene ......................................................................................................... 12 2.2 Review of other new information (since development of the draft risk management evaluation) ......................................................................................................................... 12 2.2.1 Introduction to review of other new information ............................................................. 12 2.2.2 Unintentional releases from manufacturing of chlorinated solvents ............................... 13 2.2.3 Unintentional releases from incineration processes ......................................................... 13 2.3 Development of an emission profile for hexachlorobutadiene ........................................ 14 3. Assessment of unintentional sources of hexachlorobutadiene .................................................... 15 3.1 Major unintentional emission sources .............................................................................. 15 3.1.1 Estimated global releases of hexachlorobutadiene ........................................................... 15 3.1.2 Unintentional releases from manufacture of chlorinated solvents ................................... 17 3.1.3 Unintentional releases from manufacture of Magnesium ................................................ 18 3.1.4 Unintentional releases from PVC production and manufacture of Vinyl Chloride Monomer (VCM) and Ethylene Dichloride (EDC) .......................................................... 18 3.1.5 Incineration of waste (hazardous wastes and plastic containing waste) .......................... 19 3.2 Assessment of existing control measures for major unintentional emission sources ...... 19 3.2.1 Potential control measures for unintentional emissions of hexachlorobutadiene ............ 19 3.2.2 Efficacy and efficiency of control measures .................................................................... 21 3.2.3 Positive and/or negative impacts on society of implementing possible control measures ........................................................................................................................................... 22 3.3 Monitoring data for unintentional sources of hexachlorobutadiene ................................ 22 4. Summary and conclusion ............................................................................................................. 23 4.1 Summary of information ................................................................................................... 23 4.2 Conclusion ......................................................................................................................... 24 5. References ..................................................................................................................................... 25 3 UNEP/POPS/POPRC.12/INF/12 Executive summary 1. During the ninth meeting of the Persistent Organic Pollutants Review Committee, a risk management evaluation for hexachlorobutadiene (HCBD) was presented (see Decision POPRC-9/2 and UNEP/POPS/POPRC.9/13/Add.2) and a decision made to recommend to the Conference of the Parties that it consider listing HCBD in Annexes A and C to the Convention (Decision POPRC-9/2). 2. At its seventh meeting (May 2015), the Conference of the Parties adopted decision SC-7/11, which proposed to list HCBD in Annex A of the Stockholm Convention without specific exemptions. In the same decision, the Conference of the Parties requested the Committee to further evaluate HCBD on the basis of the newly available information in relation to its listing in Annex C. This further evidence and recommendation to the Conference of the Parties on whether to list HCBD in Annex C would then be put forward for consideration at its eighth meeting (May 2017). 3. This document provides an overview of new information on unintentional releases of hexachlorobutadiene to assist the further evaluation by the Committee of the unintentional production of hexachlorobutadiene. In compiling this information the drafter has taken note of the new information provided by parties and observers of the Convention in line with Decisions SC-7/11 and POPRC-11/5. 4. As outlined in the risk management evaluation (UNEP/POPS/POPRC.9/13/Add.2), HCBD is a halogenated aliphatic compound which has been used in several technical and agricultural applications, e.g. as an intermediate in the chemical industry or as a commercial product in its own right (chemical identity see UNEP/POPS/POPRC.9/13/Add.2). In the past, it was intentionally produced and applied, e.g. as a solvent (for rubber and other polymers); as a “scrubber” to recover chlorine-containing gas or to remove volatile organic components from gas; as hydraulic, heat transfer or transformer fluid; in gyroscopes; in the production of aluminium and graphite rods; and as a plant protection product. HCBD is not known to be currently intentionally produced or used (UNEP/POPS/POPRC.9/13/Add.2). 5. HCBD is unintentionally formed and released from industrial processes and other sources. Relevant sources are (a) the production of certain chlorinated hydrocarbons, (b) production of magnesium, and (c) incineration processes (e.g. motor vehicle emissions, incineration processes of acetylene, incineration of chlorine residues where poor abatement control is in place). Releases can be minimised by alternative production processes, improved process control, emission control measures, or by substitution of the relevant chlorinated chemicals. Listing of HCBD in Annex C would subject this substance to the measures under Article 5 (measures to reduce or eliminate releases from unintentional production) of the Convention, and establish the goal of continuing minimization and, where feasible, ultimate elimination of HCBD releases. This would include an obligation to promote and require the use of best available techniques (BAT) for new HCBD sources if a Party has identified them as warranting such action in its action plan. Furthermore, parties shall promote the use of best environmental practices (BEP) for new HCBD sources, and promote the use of BAT/BEP for existing source of HCBD. Where production processes and supply chains are complex it would also mean closer tracking and monitoring of HCBD emissions from key points in the supply chain. 6. Currently, important releases of HCBD originate from the production of certain chlorinated chemicals particularly trichloroethylene, tetrachloroethylene and carbon tetrachloride. Based on this, estimates of releases can be derived from chlorine production