AN INVESTIGATION into the deaths of six tourists in Thailand earlier this year has linked toxic chemicals with the deaths.

However, investigators have failed to determine what exactly caused the deaths.

Visitors from New Zealand, Britain, France and the US died while staying at different hotels in Chiang Mai in January and February died. Another three tourists fell ill, but recovered.

The Thai Department of Disease Control said in a statement:

The specific agents that caused the deaths and illnesses in these events cannot be identified, and it cannot be determined exactly how people were exposed to them.

However, it said that at least four of those who became ill were staying in the same hotel and it is likely they were exposed to “some toxic chemical, pesticides or gas”. Two, one from New Zealand and one from Thailand, died.

The deaths of a British couple who also stayed at that hotel are “possibly related” to the other two deaths, but no known cause was found.

In May, the New Zealand TV3 programme 60 Minutes claimed that it had found traces of a toxic pesticide in her room at the Thai hotel.

The Thai government report said that it is “likely” the death of a 33-year-old American woman in January was caused by a chemical or biotoxin “and it is probably that it might have been a pesticide”.

Reuters reports that the government announced new measures today to prevent such illnesses and deaths, including better monitoring of the use of chemicals and pesticides in hotels. They also said that street food vendors and markets would be inspected by local authorities and a new website offering health advice to foreign visitors will be launched.

- Additional reporting by the AP