Staff at the Phuket Orchid Resort and Spa in Karon reportedly noticed that chlorine levels in the hotel pool were a little low this morning.
Standard practice when adding granulated chlorine to a swimming pool is to mix the chemical with water to dilute it before adding it to the feeder. A staff member apparently bypassed this step this morning, according to police, instead adding the chlorine directly to the tank.
This caused pressure inside the tank to build, they said, causing the tank to crack and release harmful chlorine gas into the air. About 100 people were reportedly around the pool at the time.
A local pool expert, who preferred to remain anonymous, said the staff member may have also added acid to the tank after the chlorine, which would cause a greater reaction.
“The only thing that would make chlorine [expand enough to crack the tank] would be to add acid to it,” he said. “The pressure would definitely build if you add powder directly [without diluting it with water], but the only thing that would make it [expand that much] is acid.
“Acid and chlorine do not mix together. You have to keep them completely separate.”
Thirty-seven guests and staff members – 26 of whom were foreigners – were taken to Patong Hospital with skin irritation and respiratory problems after the chlorine leak, before being rushed to various hospitals around Phuket Town. Several have since been released.
The most serious case is a woman who is seven months pregnant. Doctors said they are concerned for the health of the baby, and are currently conducting tests.
Low level exposure to chlorine in the air will cause eye, skin and airway irritation, as well as a sore throat and coughing. At higher levels of exposure, signs and symptoms may progress to chest tightness, wheezing, severe breathing problems, and bronchial spasms.
Severe exposures may also result in noncardiogenic pulmonary edema (fluid accumulation in the lungs which can lead to respiratory failure), which may be delayed for several hours after exposure. In particularly severe cases, inhaled chlorine may combine with body fluids and turn into hydrochloric acid in the lungs.
Chlorine gas was used as a weapon the the trench warfare of World War I.
– Paritta Wangkiat