The National Environment Agency's (NEA) letter in response to concerns about the safety of thermal fogging, gave the assurance that fogging was safe (Focus is on reducing Aedes mosquito's breeding habitats; March 10).
At the same time, NEA pointed out the precautions that infants, the elderly and pregnant women should take during misting, and that residents should "close their windows, remain indoors and cover their food and utensils".
Indeed, cypermethrin, the active ingredient in thermal fogging, is a neurotoxin and carcinogen, and causes foetal maldevelopment in pregnant mice.
In favour of carrying out thermal fogging is the claim that "fogging does not have a long residual effect on the environment".
That depends on how often fogging is carried out and whether one is able to avoid breathing the toxic fumes.
One can appreciate the need to do widespread fogging as an urgent measure in an outbreak of mosquito-carried disease. But why are private individuals allowed to carry out fogging in their own compounds?
Such fogging in a limited area is useless; it simply chases the mosquitoes away to nearby areas and allows them to return within an hour or two.
Singapore is a densely populated area. Whatever measures are taken, fogging still causes air pollution and affects residents in the area.
NEA rightly stated that routine fogging is not a sustainable measure and that source reduction is a more effective and sustainable strategy.
I believe it has in mind the prevention and elimination of stagnant water.
After being plagued by mosquitoes for more than 30 years where I live, the authorities have finally covered up the scupper drains, which were obstructed frequently by fallen leaves, and replaced them with large buried pipes. The neighbourhood has since become essentially mosquito-free.
Thermal fogging should be a measure decided on and carried out by NEA when required.
Private residents should not be allowed to do fogging in their compounds.
Ong Siew Chey (Dr)