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Unregistered ingredient detected in 11 brands of mosquito coil
Tuesday, November 15, 2005

A market survey on mosquito coils by the Consumer Council (the Council) and the Agriculture, Fisheries and Conservation Department (AFCD) showed that 11 of the 19 samples contain octachlorodipropyl ether (S-2), a pesticide active ingredient which is not registered in Hong Kong.

Suppliers are in the process of recalling the products from the market following the findings, an AFCD spokesman said today (November 15).

Acting upon an overseas report that the combustion of S-2 containing mosquito coils might release a carcinogen bis(chloromethyl)ether (BCME), the Consumer Council urged the public to stop using S-2 mosquito coils as a precautionary measure.

The AFCD said S-2 was a synergist, which could enhance the insect-killing efficacy of synthetic pyrethroid insecticides. Under the Pesticides Ordinance, Cap 133 of the Laws of Hong Kong, only registered pesticides can be imported, manufactured, sold or supplied in Hong Kong.

Enquiries made with the World Health Organization and other overseas regulatory bodies found that research on the safety of S-2 used in mosquito coils had been very limited. So far there has been no conclusive evidence that the use of S-2 containing mosquito coils can cause human cancer.

"As far as the relevant overseas report is concerned, it is restricted to a laboratory study that the burning of S-2 might release the carcinogen BCME. The study also mentions that BCME was very unstable in air and its concentration was therefore difficult to detect accurately. In another test, rats being put in separate environments with burning mosquito coils containing S-2 and without S-2 showed no difference in body conditions," the spokesman said.

The research and tests of mosquito coils by the Council and the AFCD were carried out in the past few months. As S-2 containing mosquito coils were not registered under the Pesticides Ordinance and the related ingredient information was not shown on the product label, AFCD requested suppliers to withdraw the products and produce new formulations.

Nine of the 11 brands of mosquito coils confirmed to have S-2 have almost been completely retrieved from the market, whereas the recall of the remaining two has to be completed by the end of the month.

Some suppliers have already introduced new mosquito coil formulations with no S-2 to replace the old stocks in the market. The new products will be submitted to the AFCD for testing and approval before entering the market, with packing specifying the absence of S-2 for easy identification.

Both the Consumer Council and the AFCD advise that consumers should use mosquito coils not containing S-2 to play safe, since there are alternatives available in the market. The public can dispose of S-2 mosquito coils as ordinary household refuse if they still have some left.

As a safety precaution, consumers should read the label before buying mosquito coils, maintain good ventilation (opening windows) and use in accordance with the product instructions.

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