Chemical Segration

When certain hazardous chemicals are stored or mixed together, violent reactions may occur because the chemicals are unsuitable for mixing or are incompatible. All chemicals must be stored according to chemical compatibility. See Appendix B Chemical Segregation for recommendations. Once segregated by chemical compatibility, they can then be stored alphabetically. Information regarding chemical compatibility can be found in:

• The SDS, primarily in Section 7, “Handling and Storage” and Section 10, “Stability and Reactivity”.
• Chemical Incompatibility Information Sheet
• CAMEO Chemical Incompatibility Matrix (Database for Hazardous Materials) can see what hazards might occur if chemicals are mixed together.
  • Can add chemicals to a list to always refer back to. 

If unsure of proper segregation procedures, contact the PI and/or Laboratory Supervisor or RMS for assistance. Chemical segregation can be achieved by either isolation (e.g., organic solvents stored in a flammable cabinet), physical distance (e.g., acids and bases are stored on opposite sides of a chemical storage room), or secondary containment (e.g., placing oxidizing acids such as nitric acid into a secondary containment to segregate from organic acids such as formic acid. In the most general terms, proper segregation can be achieved by:

• Storing acids away from bases and toxics;
• Storing organic acids away from inorganic acids;
• Storing flammables away from oxidizers and corrosives;
• Storing oxidizers away from organic chemicals; and
• Storing reactive and acutely toxic materials away from all other chemicals.

Segregation of different chemical hazard classes (such as acids and bases) can occur in the same cabinet as long as there is some form of physical separation, such as using trays with high sides or deep trays. However, never store oxidizers and flammables in the same cabinet. Also, do not store compounds such as inorganic cyanides and acids in the same cabinet.

If you need assistance with cleaning out your lab of old and excess chemicals, or would like assistance with segregating your chemicals, contact RMS at 940-565-2109 and/or askrms@unt.edu.