KUALA LUMPUR, July 18 — The recent cyanide poisoning case in Thailand where six people were reported dead in a luxury hotel has grabbed worldwide attention.

The six were found dead by housekeepers at the Grand Hyatt Erawan hotel in the Thai capital Bangkok late on Tuesday.

According to a BBC News report, the victims had been scheduled to check out on Monday but failed to do so.

Trirong Phiwpan, Commander of the Thai police, said police found traces of cyanide in all the six cups and suspected that one of the victims could have poisoned the drinks.

“After staff brought tea cups and two hot water bottles, milk and tea pots... one of the six introduced cyanide,” Trirong was quoted as saying.

Police also revealed there were no signs of a struggle, robbery or forced entry and also found that room’s door was locked from the inside.

Four of the victims are Vietnamese nationals Thi Nguyen Phuong, 46, her husband Hong Pham Thanh, 49, Thi Nguyen Phuong Lan, 47, and Dinh Tran Phu, 37.

The other two are American citizens Sherine Chong, 56, and Dang Hung Van, 55.

What is cyanide?

According to the New York State’s Health Department, cyanides are fast-acting poisons that can be lethal.

There are several chemical forms of cyanide:

1. Hydrogen cyanide is a pale blue or colourless liquid at room temperature and is a colourless gas at higher temperatures. It has a bitter almond odour.

2. Sodium cyanide and potassium cyanide are white powders which may have a bitter almond-like odour.

3. Other chemicals called cyanogens can generate cyanides. Cyanogen chloride is a colourless liquefied gas that is heavier than air and has a pungent odour.

How does it work?

Cyanide can quickly enter the human bloodstream after the person is exposed to the poison. The body handles small amounts of cyanide differently than large amounts.

In small doses, cyanide in the body can be changed into thiocyanate, which is less harmful and is excreted in urine.

In the body, cyanide in small amounts can also combine with another chemical to form vitamin B12, which helps maintain healthy nerve and red blood cells.

In large doses, the body’s ability to change cyanide into thiocyanate is overwhelmed. Large doses of cyanide prevent cells from using oxygen and eventually these cells die.

The heart, respiratory system and central nervous system are most susceptible to cyanide poisoning.

How much is fatal?

According to a report published in the official website of the United States’ National Library of Medicine, a lethal dose for humans is 0.05 gram per person for hydrogen cyanide or 0.15 to 0.3 gram per person for potassium cyanide.

Where is cyanide found or used?

The report by the US’ National Library of Medicine said that cyanide is used in a number of industries, such as electroplating, metal refinery, organic syntheses and various chemical processes.

The New York State’s Health Department said that dye and drug companies also use cyanide.

It also suggested that some industrial processes, such as iron and steel production, chemical industries and wastewater treatment can create cyanides.

During water chlorination, cyanogen chloride may be produced at low levels.

Recent cyanide poison cases in the region

On July 5, Nguyen Thi Hong Bich, 36, in Dong Nai Province, Vietnam, was taken into custody for allegedly murdering her 18-year-old nephew by cyanide poisoning.

In April 2023, Thai police arrested a 36-year-old woman, Sararat “Am” Rangsiwuthaporn, in Thailand, who was suspected of murdering 18 people by cyanide poisoning to avoid repaying debts she owed them.

In January 2023, the Bureau of Fisheries and Aquatic Resources in the Philippines had accused Chinese fishing fleets for allegedly pumping cyanide in the contested waters.