Incompatible Chemical Segregation
Incompatible chemical segregation is the practice of storing chemicals so they cannot mix, contact, or react if a container leaks, breaks, or spills. Under WorkSafeBC's OHS Regulation, incompatible substances must not be stored in a manner that would allow them to mix in such events. The primary source for determining incompatibility is the Safety Data Sheet (SDS), particularly sections on handling/storage and stability/reactivity.
On a manufacturing or shop floor, incompatible chemical segregation is applied by physically separating reactive chemicals using distance, cabinets, partitions, separate rooms, or separate containment to prevent a spill from reaching another chemical. This involves checking the site chemical inventory against SDS Section 7 and Section 10, then arranging storage so common incompatible pairs—such as oxidizers and flammables, acids and bases, or acids and cyanides—are not co-located without a barrier or equivalent control. The purpose is to prevent fire, explosion, toxic gas release, corrosive attack, or other dangerous reactions caused by accidental mixing. The control hierarchy prioritizes distance first, then barriers or separate storage, with more robust segregation for higher-reactivity or higher-consequence substances.
Does WorkSafeBC give a fixed separation distance for all incompatible chemicals?
The cited WorkSafeBC regulation language is performance-based: it requires incompatible substances not be stored so they can mix if leakage or breakage occurs, but it does not provide a universal numeric distance in the cited text.
What document should determine whether two chemicals are incompatible?
The SDS is the first-line reference, particularly the storage and reactivity sections.
What is the engineering control objective of segregation?
To prevent an uncontrolled reaction by ensuring that a breach in one container cannot propagate into a chemically incompatible container or shared containment system.
Is 'segregation' the same as 'secondary containment'?
No. Secondary containment captures spills; segregation prevents incompatible substances from entering the same spill volume in the first place. A site may need both controls, but containment alone does not satisfy incompatibility control if the chemicals can still mix.
What are the most high-consequence incompatible pairs on a floor audit?
Oxidizers with flammables/combustibles, acids with bases, acids with cyanides or sulfides, and any pair identified by the SDS as capable of producing heat, toxic gas, fire, or explosion on contact.