The father of a New Zealand woman who died in Thailand in February says he hopes Thai authorities will act on the recommendations of a report into her death.
Investigators found it was likely Sarah Carter, 23, died after exposure to pesticides in her Chiang Mai hotel room, though they had no firm evidence to prove her cause of death.
Her friends Emma Langlands, 23, and Amanda Eliason, 24, staying in the same room, also fell violently ill, but survived.
The report also concluded that four other people who died in Chiang Mai between January 11 and February 19 - a 47-year-old Thai woman staying in the room next to the New Zealanders, an English couple in their 70s staying on a different floor, and an American woman in a different hotel - were likely to have been killed by pesticide exposure.
It made nine recommendations to reduce further risks of chemical and pesticide exposure in Thailand.
Ms Carter's father, Richard Carter, had been critical at an initial lack of investigation, and in particular the hotel's statement that the deaths of Ms Carter and the Thai woman were coincidence, but he said today he was pleased to see the recommendations made.
"That is positive for travellers to Thailand, and I would certainly like to see all those suggested remedies put into place,'' he said.
Mr Carter said the fact a number of medical experts from Thailand and outside were involved showed it had been taken seriously.
"They certainly haven't done anything that's in any way likely to make anyone accountable, i.e. not very thorough investigation around the hotel or into the pesticide company, but they've certainly taken it very seriously in the knowledge that their tourism would drop off if they don't.''
The panel of investigators said Ms Carter and her friends developed an abnormal acid level in their circulation due to exposure to pesticides. They became ill on February 3. Ms Carter died three days later in hospital, while Ms Langlands and Ms Eliason survived.
"The clinical manifestation in the three NZ women, who were all hospitalised, can be explained by exposure to some chemicals such as those found in pesticides,'' a statement from the Thailand Ministry of Public Health's Department of Disease Control said.
Symptoms for the Thai woman were unknown as she was found dead in her room, but the statement said it was probable she died from a sudden abnormal rhythm of the heart beat and it was very likely she had the same illness as the New Zealanders.
It said the cause of the illnesses was unlikely to be bacterial or viral.
Tests on blood and biological samples returned negative results for suspected chemicals such as sodium monofluoroacetate (compound 1080) and phosphine gas.
"However, negative results from some of these toxic substances do not necessarily confirm their absence as sometimes the suspected chemical is difficult to detect or dissipates easily from the biological specimen,'' the statement said.
The recommendations included setting up a panel to recommend stricter measures for the use of pesticides in hotel and market areas, a channel to receive notification of illnesses to tourists and expatriates, and for hotel operators to use only licenced pest control companies with contracts specifying which chemicals would be used.
It also called for a food safety standard to be developed around the Night Bazaar area used by tourists in Chiang Mai, and for health education cards advising tourists about food safety and other health concerns to be made available to foreign visitors.
Mr Carter, from the southeast Auckland suburb of Howick, said he was pleased the investigation had produced something positive, but his daughter's death was still difficult to deal with.
"This is obviously rekindling the real issue a bit, so while we're pleased for this to be over, we're still obviously very saddened by the whole event.''
A French woman who died at another hotel, and whose death was also examined, probably died of a different viral cause, the report said.