Proposed Control of Poly chlorinated Naphthalenes (PCN) and Trichlorfon in 
Singapore 
 
Introduction 
The National Environment Agency (NEA) of Singapore is proposing to control 
polychlorinated naphthalenes (PCN) and trichlor fon as Hazardous Substances (HS) under the 
Environmental Protection and Management Ac t (EPMA) and EPM (Hazardous Substances) 
Regulations, and to phase-out the production, import, export and use of PCN by May 2018. 
Polychlorinated Naphthalenes (PCN) 
2 The Stockholm Convention on Persistent Organic Pollutants (POPs) is a global treaty 
to protect human health and the environment from POPs. POPs are chemicals that remain 
intact in the environment for long period of time, can be widely distributed geographically, 
accumulate in the fatty tissues  of humans and wildlife, and have harmful impacts on human 
health or the environment. 
3 PCN is a POP, which is found in cable insulation, wood preservatives, rubber and 
plastic additives, and in capacitors. According to reports published on the Stockholm Convention website, the intentional producti on of PCN has already ended. It was also 
reported in these reports, as well as publicatio ns from developed countries that the use of 
PCN has been substituted by alternatives which are already in use. 
4 Notwithstanding, PCN can be unintentionally produced during incineration or high-
temperature industrial processes. The existi ng measures to control dioxins and furans 
emissions to ensure that they fall within the stipulated limits (i.e. 0.1 ng TEQ/Nm
3 for waste 
incinerators commissioned on or after 1 Jan 2001, 1.0 ng TEQ/Nm3 for waste incinerators 
commissioned before 1 Jan 2001) under the EPM (Air Impurities) Regulations will also 
mitigate PCN emissions. 
5 At the 7th Meeting of the Conference of Partie s of the Stockholm Convention (COP-7) 
in 2015, PCN was listed in Annex A (with specif ic exemptions shown in Table 1 below) and C 
of the Convention. For chemicals listed in Anne x A of the Convention, Parties would have to 
take measures to prohibit the production, im port, export and use of the chemicals. For 
Annex C chemicals, Parties would have to reduce or eliminate the unintentional production 
of the chemicals.  
Table 1: Listing of PCN in Annex A of the Stockholm Convention 
Chemical  Activity  Specific Exemption  Polychlorinated naphthalenes, including 
dichlorinated naphthalenes, trichlorinated 
naphthalenes, tetrachlorinated naphthalenes, pentachlorinated naphthalenes, hexachlorinated naphthalenes, heptachlorinated 
naphthalenes, octachlorinated naphthalene 
  Production Intermediates in production of 
polyfluorinated naphthalenes, 
including octafluoronaphthalene  
Use Production of polyfluorinated 
naphthalenes, including octafluoronaphthalene   
 
Trichlorfon 
6 The Rotterdam Convention on the Prior Informed Consent (PIC) Procedure for 
Certain Hazardous Chemicals and Pesticides in International Trade is a global treaty to 
promote shared responsibility and cooperative efforts among Parties in the international 
trade of certain hazardous chemicals in order to protect human health and the environment. 
7 Trichlorfon, which is an organophosphate, is used in pesticides for field crops, fruits, 
vegetables, and ornamental plants. It is also  used for pest control in cattle and horses. 
Currently, there are other active ingredients that are being used as alternatives to 
trichlorfon. 
8  At the 8
th Meeting of the Conference of Parties of the Rotterdam Convention (COP-
8) in 2017, trichlorfon was listed in Annex III of the Convention. Chemicals listed in Annex III 
are subjected to the PIC procedure which involves formally obtaining the decisions of 
importing Parties on whether they wish to receive future shipments of the chemical of concern and ensuring that exporting Parties comp ly with the decisions of importing Parties. 
Proposed Regulatory Control 9 In line with the obligations of the Conventions and with the availability of 
alternatives for PCN and trichlorfon, the dome stic control measures for these chemicals are 
being reviewed.  
10 NEA plans to gazette the control of PCN and trichlorfon under the EPMA and EPM 
(HS) Regulations by November 2017. Importer s, manufacturers and distributors of these 
chemicals and products containing these chemic als will have 6 months from the date of 
gazette to comply with the control measures. With effect from May 2018, the production, 
import, export and use of PCN in Singapore will not be allowed. A HS Licence will be 
required for companies that import, export and sell trichlorfon, while end-users that store 
and use trichlorfon will be required to obtain a HS Permit.