Never mix Sodium dichloroisocyanurate with Sodium carbonate
Toxic gas
Chlorine gas is released. The regulator lists soda ash — washing soda — among the substances sodium dichloroisocyanurate is not compatible with, alongside ammonia, amines, strong bases, oxidising agents and hydrogen peroxide. Chlorine irritates the eyes, nose, throat and lungs and its effects can be delayed. Ventilate by leaving, not by staying.
Precautions
- Never mix with other cleaning products
- Ventilate the area
- Keep away from children and pets
- Rinse thoroughly afterwards
How this happens
The chlorine donor releases its chlorine when its chemical environment changes, and a strongly alkaline carbonate solution is one such change. The circumstance is what matters: washing soda is promoted for soaking, and a sanitising tablet is promoted for soaking, so the accident is a bucket used for one and then the other rather than a deliberate combination.
If it has already happened
Get everyone into fresh air straight away, and do not go back inside to open windows. Anyone with breathing difficulty, chest pain, persistent coughing, or a chemical splash to the eyes needs medical attention — treat it as an emergency and call your local emergency number. In the United Kingdom, use NHS 111 or 999 as appropriate; clinicians can consult the National Poisons Information Service.
The substances involved
- Sodium dichloroisocyanurate — The chlorine donor in sanitising and sterilising tablets. A state health department records it as reacting explosively with bleach in the presence of water.
- Sodium carbonate — A considerably stronger alkali than bicarbonate. Effective on grease and as a laundry builder, and damaging to aluminium, wool and painted surfaces.
Evidence
Supported
Sources
Right to Know Hazardous Substance Fact Sheet: Sodium Dichloro-Isocyanate (RTK 1694)
New Jersey Department of Health, 2002 · Government or regulator
Relied on for: That sodium dichloroisocyanurate is not compatible with soda ash, ammonia, amines, strong bases, oxidising agents and hydrogen peroxide, and that it reacts with water to produce chlorine gas and nitrogen trichloride. (states this directly)
Safety Data Sheet: Sodium Carbonate
Murphy and Son Ltd · Manufacturer documentation
Relied on for: That sodium carbonate is soda ash and is a strongly alkaline solid used in cleaning. (states this directly)