Chemical Compatibility Chart

What Is Chemical Compatibility Chart?

A chemical compatibility chart is a reference matrix showing which chemicals can be stored, mixed, or transported together without triggering a dangerous reaction (fire, explosion, toxic gas release, or violent polymerization). Fire departments and hazmat teams use them two ways: proactively, to check storage segregation at a fixed facility during a pre-plan inspection, and reactively, during an incident, to predict what happens if two spilled or leaking products come into contact. Common incompatible pairs responders are trained to flag include oxidizers with flammables, strong acids with cyanide or sulfide salts (which liberates HCN or H2S gas), and household bleach with ammonia-based cleaners (chloramine gas). CAMEO Chemicals' reactivity worksheet and the DOT segregation tables (49 CFR 177.848) are the two references most commonly pulled on scene.

Why Chemical Compatibility Chart Matters on the Fireground

A compatibility chart is often the only thing standing between a routine spill and a secondary chemical reaction that injures the entry team. Checking it before combining, neutralizing, or even co-locating containers in the same containment area tells you whether you're about to create a toxic gas, an exotherm, or a fire you didn't plan for.

Relevant NFPA Standards

• NFPA 470: Hazardous Materials/Weapons of Mass Destruction (WMD) Standard for Responders
• DOT 49 CFR 177.848: Segregation table for hazardous materials

Field Procedures & Tactical Steps

1. Pull the SDS or shipping papers for every product involved before assuming compatibility.
2. Cross-check suspected pairs against a reactivity reference (CAMEO Chemicals worksheet or DOT segregation table) rather than relying on memory.
3. Keep incompatible spills in separate containment and route decon runoff separately if any of the products involved are flagged as reactive with each other.
4. Brief the hazmat group supervisor on any confirmed incompatibility so entry and decon assignments account for it before teams commit.

Common Context & Application

Pulled up during pre-incident planning visits to facilities with mixed chemical storage, and again mid-incident whenever a spill involves more than one product, to decide whether they can be contained together or need separate berms and separate decon lines.

Frequently Asked Questions about Chemical Compatibility Chart