A group of doctors said in a press conference arranged by Agricultural Science Foundation yesterday that paraquat, a widely used herbicide in Thailand, is not harmful to health, unless people directly drank it or bathed in it, and it should be allowed for use in farming.

They also denied that there was a connection between exposure to paraquat and necrotising fasciitis (known as the “flesh-eating disease”), Parkinson’s disease, and slower child development. This is in conflict with earlier medical warnings that found that paraquat exposure and contamination in the environment could lead to these health threats, especially among farmers and pregnant women.

Respiratory diseases expert and member of Royal Society Office Dr Somchai Bavornkitti

Respiratory diseases expert and member of Royal Society Office Dr Somchai Bavornkitti said there was still no reliable scientific proof to confirm a link between paraquat exposure to diseases such as necrotising fasciitis and Parkinson’s, and it was unlikely that paraquat could contaminate the environment, as the substance could be easily neutralised with soil.

“I still cannot see how paraquat can get into your body, as when spraying paraquat in the field, it will diffuse in the air in droplets that are far larger than those able to be inhaled into the lungs,” Somchai said.

He dismissed the claim that paraquat contamination in water contributes to necrosis. If paraquat actually contaminated the water, it would be too attenuated to cause any harm to health, he said.

Somchai said he suspected that patients with necrosis already had cuts or wounds and it was bacteria or parasites in the water that actually caused the infection.

Somchai also mentioned cases where traces of paraquat were found in newborn babies, and claims that the development of children who had a record of exposure to paraquat was slow. He said there had to be more research on this issue to confirm these suspicions and discover how paraquat could enter a mother’s body and be transmitted to the baby in the first place.

“From my point of view, paraquat is safe enough to use and has more benefits than harm, compared to glyphosate (another herbicide), where there is scientific evidence that it can contaminate the environment and cause harm to people’s health. It should be glyphosate that is banned, not paraquat,” he added.

Director of the Emergency Physicians College Dr Surajit Suntorntham

Director of the Emergency Physicians College Dr Surajit Suntorntham said that in emergency medicine, the only sickness and death related to paraquat was in patients who intentionally or unintentionally consumed the herbicide, causing internal-organ failure.

“In term of toxicology, every substance on earth is poisonous, if consumed in enough quantity. For instance, if we drink more than 12 litres of water within 24 hours, we could lose the sodium balance in our bodies and die from hyperhydration,” Surajit said.

“Paraquat is the same. It is no doubt poisonous, but only when someone is exposed to a very high volume of paraquat by eating or skin contact can it cause a health threat. So, we should find better ways to use it safely rather than ban it totally.”

He noted that the United States not only allows the use of paraquat, but has increased the amount of paraquat usage in its agricultural sector without jeopardising the health of it citizens.

Surajit said that the US avoids health risks from paraquat by imposing strict safety regulations. For instance, physical exposure to the substance is reduced by delivering paraquat to famers in ready-to-use packages, so they can spray it onto weeds without having to prepare and dilute the chemical themselves.