Chiang Mai tourist death probe finds no common link – PR campaign launched to protect tourism industry (video)

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Improper handling of pathology samples and limited cooperation by relatives are blamed by Thailand authorities for scientists on four continents being unable to determine a causative agent or a common factor linking the deaths of five tourists and a Thai tourist guide in the Northern City of Chiang Mai earlier this year.

The investigation focused particular attention on the Downtown Inn, Chiang Mai, which was a common factor in four of the tourist deaths
The investigation focused on the Downtown Inn, Chiang Mai, which was a common factor in four of the tourist deaths Chiang Mai Locator

After five months of investigation and thousands of laboratory tests the investigative panel formed to probe the Chiang Mai tourist death cluster yesterday handed down a report that raises more questions than it answers, while at the same time announcing a raft of new initiatives to protect the region and country’s precious tourism industry from dangers that it says weren’t responsible for the deaths of tourists in Chiang Mai earlier this year.

The investigation panel was established to examine the cause of deaths of:

  • Soraya Pandola (age 33) who died on January 11, 2011 and her Canadian colleague (age 29) who fell ill
  • An unnamed French woman (age 25) who died on January 19, 2011
  • Waraporn Pungmahisiranon (age 47), a Thai tourist guide, who died on February 3, 2011
  • Sarah Carter (age 23) who died February 6, 2011 and her two companions (both age 23) who both fell ill
  • George and Eileen Everitt, (age 78 and 74) who both died on February 19, 2011

A particular focus of the investigation was the Downtown Inn in the night market section of Chiang Mai City, where three of the deaths occurred (Sarah Carter was transported from the hotel and later died in hospital), and which other people who died were said to have had some casual contact with.

A report by the New Zealand 60 Minutes television programme, To Die For, in May this year strongly implied the Dow Chemical Co.’s pesticide chlorpyrifos was to blame (See: Dow chemical’s chlorpyrifos pesticide found in Chiang Mai tourist death hotel), though this was dismissed by the investigative panel (See: Thailand authorities dismiss chlorpyrifos as cause of Chiang Mai hotel tourist deaths), as well as by New Zealand’s three leading toxicology experts (See: War of words over Chiang Mai tourist deaths report).

Chiang Mai Provincial governor; Mom Luang Panadda Diskul – maintained the deaths "a coincidence"
Chiang Mai Provincial governor; Mom Luang Panadda Diskul – maintained the deaths “a coincidence”

The deaths also saw the establishment of the Thailand Travel Tragedies website (See: Lost smiles in LOS as Thailand travel tragedies website goes live) by the family of Ms Carter and more than a handful of accusations of a cover-up by Chiang Mai authorities.

Accusations of collusion, nepotism, malfeasance, and a whole raft of conspiracy theories ranging from toxic seaweed and poison puffer fish being sold as salmon, to a serial killer stalking Chiang Mai tourists and poisoning them were also floated.

All the while Chiang Mai Provincial Governor, Mom Luang Panadda Diskul, maintained that the Chiang Mai tourist deaths were “a coincidence”.

In its fifth and presumably final report into the Chiang Mai tourist deaths, Thailand’s Department of Disease Control (DDC) said, ‘as most of the deceased were foreign nationals and there were no evidence of a criminal cause, their bodies were quickly turned over to relatives who took them home.

‘Some relatives also did not want an autopsy to be performed, consequently biological samples were limited and in most cases were insufficient for the large number of tests that had to be considered and undertaken.

‘Certain tests also require that samples be taken by a particular method and stored and transported in special containers. This was not possible because the need for testing for these toxic causes were not foreseen at the time of death’.

The report says more than 350 drug, chemical, and organism tests were done on each fatality, with some 1,250 tests performed on samples taken from Ms Carter in laboratories in Thailand and overseas.

The report said that although ‘experts ultimately could identify the likely cause of death for most cases’, the investigation was unable to identify a common factor linking all of the deaths, a causative agent, or how those tourists who died in Chiang Mai might have been exposed to it.

Pesticide link in Chiang Mai tourist deaths

A public health worker fogging against mosquitoes in Bangkok
A public health worker fogging against mosquitoes in Bangkok Sakchai Lalit/AP

Regarding the deaths of Soraya Pandola and Sarah Carter, the investigation found ingestion of pesticides may have been to blame, though no traces of organophosphate (OP), organochlorine, or carbamate pesticides, such as chlorpyrifos, were found in the clinical specimens and blood test.

In the death of Ms Pandola, who did not stay at the Downtown Inn, the investigation found she died from myocardial injury (damage to the heart muscle), with the suspected agent that caused her death most likely to be chemical or biotoxin in nature.

‘It is probable that it might have been a rodenticide. However, the exact agent could not be identified because the quantity of sample from the case was insufficient’.

While Ms Pandola and her companion may have become ill from the same causative agent, the report concludes that there is nothing to link the death of Ms Pandola to any of the other Chiang Mai tourist deaths.

In the death of the unnamed French woman, who also did not stay at the Downtown Inn and whose illness is said to have manifested before arriving in Chiang Mai, the cause of death was attributed to acute severe myocarditis due to a viral infection, rather than exposure to a poison. Laboratory tests in Thailand and at the US-CDC found ‘symptoms and inflammatory cells throughout her heart’.

In the deaths of Thai tour guide, Waraporn Pungmahisiranon and Ms Carter, whose deaths occurred within three days of each other, the investigation found the likely cause of the illnesses and deaths of the two women, along with two other New Zealand tourists who got ill at the same time, is the same given the timing and the proximity of their rooms.

Chlorpyrifos not found in Chiang Mai tourist death tests

Though Ms Waraporn’s symptoms prior to her death are unknown, the report states the symptoms exhibited by the three New Zealand tourists, ‘can be explained by exposure to some chemicals, such as those found in pesticides which contain aluminum or zinc phosphide’.

Aluminium is a common ingredient in body spray antiperspirants
Aluminium is a common ingredient in body spray antiperspirants The Mercury

Investigations of the two rooms the New Zealanders and Ms Waraporn stayed in found aluminium molecules on carpet samples, though the report notes that aluminum is an ingredient in paint and air-conditioning cleaning fluids and that aluminum molecules were also found in other rooms sampled throughout in the hotel. (Ed: Aluminium is also an ingredient in many antiperspirants and deodorant body sprays).

Addressing the 60 Minutes “theory” that chlorpyrifos was to blame for the Chiang Mai tourist deaths, the reports states, ‘insecticides in the organophosphate, organochlorine and carbamate group, such as chlorpyrifos, are also unlikely to be the cause, because they conflict with clinical specimens and blood tests’.

In their letter to the 60 Minutes disputing the imputation that chlorpyrifos was to blame, New Zealand’s three top toxicology experts said all ‘OPs cause depression of acetylcholinesterase and as the bonding of OPs to this enzyme is chemical, regeneration of levels in blood can only arise from replacement of blood cells and this usually takes up to six weeks, so the depression would have been found’ (See: War of words over Chiang Mai tourist deaths report).

The report also said tests at the US-CDC and German laboratories on samples from the three New Zealanders returned negative results for chemicals such as sodium monofluoroacetate (compound 1080) and phosphine gas, a widely used, cost effective, fumigant that does not leave residue and which contains aluminium.

The report also noted that the three New Zealand women had severe metabolic acidosis (high blood acid levels), and all three suffered myocardial injury, with Ms Carter dying from heart and kidney damage.

In relation to Ms Waraporn, the investigation found ‘it is most likely she died from sudden cardiac arrhythmia’ (abnormal rhythm of the heart beat), with a postmortem examination finding she had a 40 per cent occlusion of the right coronary artery.

Regarding the deaths of English husband and wife George and Eileen Everitt, who were found dead in their rooms at the Downtown Inn and which Thai authorities speculate suffered almost simultaneous heart failure (preventing one from calling for assistance for the other if not simultaneous), though on a different floor to the others. The investigative committee determined death was caused by a cardiac event or arrest, supported by evidence of 40-80 per cent occlusion in three coronary arteries in Mr Everitt and 30-60 per cent occlusion in the coronary arteries of Mrs Everitt.

No smoking gun in Chiang Mai tourist death probe

New Zealand's three top toxicologists fired off an angry letter to 60 Minutes saying the parents and those interested in the Chiang Mai tourists deaths now know no more than before. Click to view the full letter
New Zealand’s three top toxicologists fired off an angry letter to 60 Minutes saying the parents and those interested in the Chiang Mai tourists deaths now know no more than before. Click to view the full letter

The report concludes with: ‘Despite the best efforts of the Thai authorities and their international partners in undertaking an exhaustive investigation, the specific agents that caused the deaths and illnesses in these events can not be identified and it can not be determined exactly how people might have been exposed to them’.

While the investigative panel might claim the battery of tests were unable to identify a causative agent, the conundrum posed is that from a spate of tourist deaths in Chiang Mai over a five week period, six people aged between 23 and 78 all died as a result of heart related illnesses. Two others survived after they received treatment for damaged hearts.

Discussing the then current investigation with New Zealand toxicologist Dr John Reeve several weeks ago, he speculated the final report into the Chiang Mai tourist deaths might indeed come up empty-handed, stating “it’s possible a cause won’t be found. These clusters occur from time to time and while it’s quite bizarre, if it’s a virus it might be very difficult to find”.

Final report into the deaths of five foreign tourists and one Thai tourist guide in Chiang Mai, Northern Thailand
Final report into the deaths of five foreign tourists and one Thai tourist guide in Chiang Mai, Northern Thailand

In the wake of the report Dr Reeve said he is still not surprised the investigation failed to identify the causative agent, though he is somewhat bewildered by the statement the pathology samples were not handled correctly and doesn’t know what agent Thai authorities think they might have missed, or what special handling requirements they are referring to.

“If you don’t know what you are looking for in the first place, even with modern toxicology screening equipment able to conduct 230 screens at a time, it can be very difficult to find a causative agent. Personally I don’t believe a pesticide is involved and I still wouldn’t rule out a viral cause, as it still fits the symptoms from what I know of them.

“I can’t think of a single pesticide available in New Zealand that could cause death unless deliberately consumed and the consumer being aware of it from the taste or smell, with the only chemical readily coming to mind which suits the symptoms being ethylene glycol*, which has often been used in wine and other alcoholic drinks.

Predictably the failure of the investigation to unearth a smoking gun or to identify a factor and/or person to be held responsible has sent those prone to believe in conspiracy theories and cover-ups into a frenzy, while the admission by Thai authorities that pathological samples taken from the victims were not handled correctly is puzzling.

New measures to guard against previously unknown danger

While some may find the wording of the final report presents nothing more than a conundrum, provincial and national authorities have displayed outstanding initiative in attempting to crisis manage the questions left hanging by the Chiang Mai tourist death committee’s final report.

Final report into the deaths of five foreign tourists and one Thai tourist guide in Chiang Mai, Northern Thailand
Final report into the deaths of five foreign tourists and one Thai tourist guide in Chiang Mai, Northern Thailand

On the evening before the final report was made public, but embargoed to coincide with the Chiang Mai media conference at which the results were announced, unembargoed copies of the report’s contents were distributed and posted on blogs such as this one and emailed to journalists who have followed the events, along with a whole raft of supporting documents (see links below), all in fluent English – a novelty in Thailand.

While Thai authorities say no significant levels of pesticide or chemicals were found in the Chiang Mai tourist death victims’ pathology samples, they have wheeled out a raft of new measures designed to prevent something from happening that they claim there is no proof of ever having happened before.

Aimed at reducing the risks of chemical and pesticide exposure to future visitors to Chiang Mai, officials from the DDC vow to apply the same measures to other main tourist provinces as well.

New safety measures for chemical use in Thailand

The new measures announced by Chiang Mai authorities are:

1) Establishment of a panel to investigate and recommend stricter measures for the use of chemicals, including pesticides, in hotel and market areas.

2) A channel to receive notification of ill tourists and expatriates. Visitors can post their notification at, or call +66 (0)53 216 592 with a guarantee that  all events will be verified and investigated.

3) The surveillance of hospitalised tourists already in effect will continue and a new protocol for investigation of fatal cases developed and implemented.

4) Retailers of household and agricultural chemicals (pesticides) must declare a watch list of products whose procurement and sales are to be closely monitored. The provincial health office will carry out periodic checks on these items.

5) Hotel operators must use only licensed pest control companies and their contracts must specify which chemicals are to be used. Samples will be collected and sent for testing by the authorities twice a year.

Final report into the deaths of five foreign tourists and one Thai tourist guide in Chiang Mai, Northern Thailand
Final report into the deaths of five foreign tourists and one Thai tourist guide in Chiang Mai, Northern Thailand

6) Municipal authorities to give safety advice and monitor public celebrations where the burning of ritual papers and other materials are performed in communities, temples, and shrines as part of traditional festivals.

7) Food safety standards at eateries and among street vendors, especially around the night bazaar area frequented by tourists in Chiang Mai, are being reviewed and revised to assure safety and compliance.

8) Health Education Cards to advice tourists about food safety and other health concerns will be made available to foreign visitors to the province.

9) The Ministry of Public Health will apply these measures to safeguard tourists in other provinces.

While the measures announced might just amount to little more than a good PR exercise and Thai authorities attempting to reassure nervous tourists, the new measures, coupled with the inconclusive nature of the report, is no doubt one “coincidence” that Mr Panadda hopes never occurs in Chiang Mai again.


(Ed: A toxic dose of ethylene glycol requiring medical treatment varies, but is considered more than 0.1 mL per kg body weight (ml/kg) of pure substance, or about 16ml (0.54oz) of 50 per cent ethylene glycol for an 80kg (176lb) adult. The orally lethal dose in humans has been reported as approximately 1.4ml/kg of pure ethylene glycol, or about 224ml (7.57oz) of 50 per cent ethylene glycol for an 80kg adult, although death has occurred with just 30ml (1oz) of the concentrate in an adult.)



Feature video Reuters/ Bangkok Times Online






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John Le Fevre is an Australian national with more than 40 years experience as a journalist, photographer, videographer and editor.

He has spent extensive periods of time working in Africa and throughout Southeast Asia, with stints in the Middle East, the USA, and England.

He has covered major world events including Operation Desert Shield/ Storm, the 1991 pillage in Zaire, the 1994 Rwanda genocide, the 1999 East Timor independence unrest, the 2004 Asian tsunami, and the 2009, 2010, and 2014 Bangkok political protests.

In 1995 he was a Walkley Award finalist, the highest awards in Australian journalism, for his coverage of the 1995 Zaire (now Democratic Republic of Congo) Ebola outbreak.

Most recently he was the Thailand editor/ managing editor of AEC News Today . Prior to that he was the deputy editor and Thailand and Greater Mekong Sub-region editor for The Establishment Post, predecessor of Asean Today.

In the mid-80s and early 90s he owned JLF Promotions, the largest above and below the line marketing and PR firm servicing the high-technology industry in Australia. It was sold in 1995.

Opinions and views expressed on this site are those of the author’s only. Read more at About me

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2 Responses to "Chiang Mai tourist death probe finds no common link – PR campaign launched to protect tourism industry (video)"

  1. Devin   August 28, 2011 at 1:13 pm

    Thanks for this article. The unanswered questions regarding the deaths of these tourists are extremely problematic, and hopefully the common link is eventually found. With this ongoing scandal and the recent murder of a New Zealand citizen, it makes sense that the government is now very concerned about protecting the tourism industry. Although these poisonings were a big deal, I still think that this is a rare incident, and Thailand should not be considered a dangerous tourist destination because of it. If anything, the high rate of car accidents in Thailand should be the concern for tourists. I’m sure many more tourists die each year in car accidents than from chemical poisoning. That being said, if any tourists are the victim of poisoning, and survive, they should definitely report this to the proper authorities and think about hiring one of the many Thailand lawyers who will take their case.

  2. rfdunedin   August 19, 2011 at 11:30 am

    Another top piece of journalism, John. This continues to be a public relations disaster for the wonderful town of Chiang Mai and its people. As you say: “A report that raises more questions than it answers”. Chiang Mai Provincial governor; Mom Luang Panadda Diskul who “maintained the deaths “a coincidence”. should be held accountable. In my opinion, as an appointed official, he should be recalled by the new Bangkok Government to show that lax practices will not be tolerated.


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