Material Safety Data Sheet User's Guide​

9. Reactivity data

Conditions of chemical instability Hazardous decomposition products
Name or class of substances with which the product is incompatible Polymerization *
Conditions of reactivity  

*Non-essential information for WHMIS purposes.


 

Conditions of chemical instability

This information indicates whether a substance is stable and, if need be, indicates the conditions that produce chemical instability.

 

Example

Sodium hypochlorite gives off toxic fumes of chlorine when it is heated. Appropriate ventilation must be provided to ensure that the permissible limit values are not exceeded.


Stability-1 Stability-2 Stability-3 Stability-4

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Name or class of substances with which the product is incompatible

This subsection indicates whether a product must not be brought into contact with certain specified substances, and if need be, specifies the nature of the hazard if the product is brought into contact with these substances.

 

Example

12% bleach is incompatible with strong acids. On contact, it gives off toxic chlorine vapours.

Incompatibility

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Conditions of reactivity

This indicates whether a substance is likely to react violently or dangerously under normal conditions of use. If need be, the nature of the hazard is specified.

 

Example

12% bleach is unstable in the presence of light and metals or when the pH of the solution becomes less basic.

 

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Hazardous decomposition products

This subsection lists the products that are health and safety hazards that are likely to form when a substance decomposes. Decomposition may be the result of a reaction occurring at room temperature, exposure to light, or the effect of heat on the substance, etc.

 

Example

Ammonia: thermal decomposition (begins between 450°C and 500°C), giving off nitrogen and hydrogen.

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Polymerization

This subsection indicates whether the substance can change into a polymer (the combining of several molecules) and under what conditions this change occurs. The heat given off and/or the expansion in volume caused by the polymerization reaction could cause the container to burst and the remaining product (unpolymerized) to spill. These accidents can be avoided by controlling the polymerization conditions.

 

Example

Exposure to light or contact with strong acids or bases can cause acrolein to polymerize.

Polymerisation

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