When mixed with water, caustic soda can release fumes that are irritating to the lungs and throat.
Caustic soda is highly effective, but it isn’t a cure-all. It works best on: caustic soda drain blockage
Remove any standing water from the sink or basin if possible. If the water is too deep to bail out, you may need to wait for it to drain slowly or use a wet/dry vacuum. Caustic soda works best when applied directly to the blockage rather than being diluted by a basin full of water. When mixed with water, caustic soda can release
This is the most dangerous mistake a homeowner can make. Never use caustic soda if you have recently poured a different drain cleaner (especially an acid-based one) down the sink. Mixing caustic soda with acids or bleach can create chlorine gas or other lethal fumes. If the drain was treated recently, flush it thoroughly with water first or wait a few days. If the water is too deep to bail