Corrosive agents not for home use, say experts
An air-conditioning technician and a chemist have warned that acidic cleansers can be risky if handled improperly and should be used only in industrial settings rather than the home.
The cleanser that dripped on people yesterday is believed to have been hydrochloric acid, a highly concentrated industrial chemical.
Air-conditioning technician Fung Cheung Kwan advised the public not to handle the acid by themselves.
'Not many people know how to dilute this concentrated acid, and don't know how much they need to clean an air conditioner, because different situations require different levels of thinning,' he said.
The best way was to hire a professional technician to clean an air conditioner.
'There are certainly risks, because it's not just taking parts out of the air conditioner to clean, you need to have the skills,' he said, speaking from 30 years of experience.
'Most people just purchase the cleanser from the hardware store, but they don't know exactly what type of chemicals they are using.'
University of Hong Kong associate professor in chemistry Fung Ying-sing said hydrochloric acid was often employed to remove rust and stains in industry, but seldom used at home.
'I'm not sure how concentrated or diluted the chemical was when it was used, but if it was a chemical for industrial use, it would usually not have been diluted,' said Professor Fung.
The acid could seriously damage sensitive areas such as the eyes, and protective clothing was needed when using it.
He suggested users needed to be geared up with proper clothing and gloves for protection when using this chemical.
He said most people usually used dust cleansers to wash off layers of debris inside their air conditioners, such cleansers being less corrosive and safer to use.