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 catalogue does not publish conditions or proportions for this, because a mechanism paired with quantities reads as a method. What is worth stating is the circumstance: 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.
CleaningHQ describes what kind of reaction this is and what it does to a person. It does not publish concentrations, quantities or conditions, because a warning specific enough to be followed is not a warning.
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
Two sources are needed here rather than one, because the finding depends on an identification: the regulator's sheet says soda ash, and the safety data sheet establishes that soda ash is the washing soda this catalogue already holds a record for. Recorded at supported rather than strongly supported because the sheet lists an incompatibility without describing the domestic outcome, and this record does not invent one beyond what the chlorine chemistry establishes.
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)
Verification: a person has read the passage relied on.
Read on — The 'IDENTIFICATION' paragraph and the 'HANDLING AND STORAGE' reactivity list. Supports the claim as stated. Adds an agent and two incompatibility records. The tablet-plus-bleach pairing is a genuinely new hazard for this catalogue and it is not one any consumer cleaning publication consulted during this sprint carries.
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)
Verification: a person has read the passage relied on.
Read on — Section 10.5, Incompatible materials. Supports a narrower statement — our claim was reduced. The incompatibility itself is now directly evidenced by a document that was read, and the sodium-carbonate-on-aluminium edge no longer rests on two unread reference works. What is NOT evidenced by it is the mechanism: the amphoteric-attack and hydrogen-evolution account remains an interpretation from general chemistry and is labelled as one. Sprint 6 found the equivalent statement for sodium HYDROXIDE and correctly declined to carry it across; this is the carbonate-specific source that declining required.
Last reviewed by a person on .
Last reviewed by a person on .