What does chemical incompatibility mean?
Two products are incompatible in a given scenario when their contact could produce a hazardous reaction, such as the release of heat, gas formation, fire, or pressure increase. Incompatibility with container materials, absorbents, water, or other foreseeable conditions must also be considered. The question is what types of contact are likely to actually occur in the installation.
It’s not just about preventing deliberate mixing. A leak can combine products that appeared separate, a tool can transfer residue, and waste can contain components no longer identifiable by their trade name. The assessment must follow the product’s entire journey, from receipt to disposal as waste.
Where to find the information
The safety data sheet provides information on handling and storage, as well as stability and reactivity, particularly in sections 7 and 10. Emergency instructions and any specific supplier requirements should also be reviewed. The information must correspond to the formulation being used, not to a similarly named version.
General tables help identify issues that require further investigation, but they are not a substitute for specific testing. A broad group, such as acids or organic products, may exhibit different behaviors. When the information is insufficient, competent personnel or the supplier are consulted before authorizing a storage combination, transfer, or cleaning procedure.
Scenarios that need to be studied
The assessment must cover receiving, internal transport, storage, dosing, maintenance, and disposal. At each stage, potential contacts, their causes, and the barriers preventing them are identified. Connection errors, backflow through a pipe, illegible labels, or the reuse of a container can be as significant as a broken container.
Emergency scenarios are also analyzed. A common spill containment area can collect spills of products that should never be mixed; a drain can carry a leak to another area. The selection of absorbents and extinguishing agents must be compatible with the products and the response plan, avoiding unevaluated universal solutions.
Separation in storage
Storage must be organized according to hazards, incompatibilities, and applicable requirements. Alphabetizing all products without prior segregation may result in incompatible products being stored together. Similarly, placing them on different shelves is insufficient if a spill could fall from one shelf onto another .
The Chemical Storage Regulations and their supplementary technical instructions establish requirements on a case-by-case basis. Their scope of application and the necessary design must be verified. Segregation may require specific solutions for location, containment, or separation; there is no single distance that will resolve all combinations of products, quantities, and containers.
Use, cleaning and waste
The workstation uses identified and compatible containers and connections. Shared equipment must be monitored to ensure it is properly handled, as it can transfer traces of one substance to another. Cleaning requires a procedure that considers the previous product, the cleaning agent, and the next use, especially for dispensing or mixing equipment.
Waste contains chemical hazards and can develop other hazards through combination or degradation. It must be identified and segregated according to established procedures, without being grouped together simply because it is liquid or comes from the same section. The management of seemingly empty containers also requires consideration of any remaining residue. A waste drum is not a safe solution for all leftover materials.
Practical example
A warehouse has two groups of products stored separately on shelves, but their spill containment trays empty into the same collection area. Document review identifies an incompatibility between them. Although the containers do not touch, a scenario involving simultaneous leaks or spill cleanup would allow the liquids to come into contact.
The improvement redefines the containment and response procedure, updates the layout, and verifies the path of a leak without using hazardous materials. Reception and cleaning are informed, as both can alter the planned arrangement. The closure of the action is based on demonstrating that potential contact has been stopped, not simply on posting a new sign.
Responsibilities and changes
The approval of a new product must include a review of its compatibility with existing inventory, equipment, and waste. Purchasing should not introduce an alternative based solely on commercial equivalence without communicating it to those who assess the risk. The update must reach the warehouse and the workstations where it is used.
It is advisable to maintain a controlled record of incompatibilities and storage conditions, referencing the technical sources used. Changes in formulation, quantity, container, location, or cleaning method may require review. Even minor issues, such as leaks or incorrect connections, provide information about scenarios that the initial design did not adequately consider.
Common mistakes
Sharing a pictogram does not guarantee compatibility. Neither does the fact that two products are from the same supplier, have been stored together without incident, or are in sealed containers. Prevention measures must consider foreseeable failure and the consequences of contact, not just normal operation.
Another mistake is mixing cleaning products to increase their effectiveness or neutralize residues without an authorized technical procedure. In the event of an unexpected reaction, the established response should be activated, exposure avoided, and specialized help sought as needed. Incompatibility control should be integrated into routine work so that it doesn’t depend on recalling a list from memory.
