Akzo left-hand thread coupling specifically for sodium hypochlorite
An Akzo coupling with left-hand thread was developed especially for sodium hypochlorite. Sodium hypochlorite reacts violently with acids to produce toxic chlorine gas. Thus, sodium hypochlorite should be avoided from coming into contact with acids as large amounts of chlorine gas can be released. Chlorine gas can damage the respiratory tract and lungs.
For added safety and to avoid unintended events, the complete fitting is made of white polyethylene (HDPE) and has a left-hand thread especially for loading sodium hypochlorite. This in order to prevent a truck driver from accidentally mixing sodium hypochlorite with acids by connecting to the wrong tank, the coupling simply does not fit the black Akzo fitting with right-hand thread.
In the Netherlands, the use of this special coupling is even required by law for all sodium hypochlorite loading and unloading sites.