Introduction to the Chemical Reactivity Worksheet

The Chemical Reactivity Worksheet is software that you use to find out about the potential reactive hazards of substances and mixtures of substances.

To use the Worksheet, you select chemicals from its database, and add them to a "mixture." The Worksheet then predicts the reactivity of this mixture. (There are 6,113 chemicals and chemical mixtures in the database; these are the same ones that you'll find in the CAMEO (Computer-Aided Management of Emergency Operations) chemical database.)

You also can use the Worksheet to check any chemical's intrinsic reactive properties, such as flammability, peroxidizability, polymerizability, and radioactivity.

How the Worksheet Works

Each substance was assigned to one or more reactive groups, based on the known chemistry of that substance. Reactive groups are categories of chemicals that are assumed to react in similar ways because they are similar in their chemical structure.

• To see descriptions of all the reactive groups we defined, from the Mixture Worksheet, click Reactive Groups (lower middle of screen).
  
• To see which reactive groups include a particular chemical, perform a search for the chemical, then, on the "Search Results" card for that chemical, click the Additional Information tab to see the Reactive Group(s) it's in.

To predict the reactivity of a mixture of chemicals, the Worksheet first identifies the reactive groups to which the chemicals belong, and then predicts the kinds of chemical reactions likely to occur when members of these groups are mixed together.

You can mix groups rather than specific chemicals, and might wish to do so if

• you know the chemical class of a chemical, but not its exact name or CAS (Chemical Abstracts Service) registry number. For example, you may be able to tell it's a powdered metal (which would typically be used in manufacturing processes as a reducing agent or catalyst);
  
• it's not in the Worksheet's database, but its MSDS (Material Safety Data Sheet) says what chemical class it's in (or you happen to know its chemical class). This would be most likely for a new compound that hasn't yet been included in major chemical databases. (CAMEO assembles chemicals from many major public databases.)

The Worksheet only predicts the reactivity between two chemicals at a time. Be aware that

• sometimes, three or more chemicals can react together in ways the Worksheet can't predict. For example, sulfuric acid, nitric acid, and glycerine react together to produce nitroglycerine (the Worksheet recognizes that this mixture would be very reactive, but does not predict that nitroglycerine would be produced);
  
• one chemical can catalyze (speed up) the reaction between other chemicals. For example, nickel carbonyl catalyzes many polymerization reactions and other kinds of synthetic organic reactions. The Worksheet cannot predict when a reaction between two chemicals could be speeded up by another chemical.

However, reactions among more than two chemicals are relatively uncommon in nature (except for the catalyzed reactions that are common components of the metabolic processes of living organisms).

A Brief History of the Worksheet

In 1980, the Hazardous Materials Management Section of the California Department of Health Services prepared a manual for the Environmental Protection Agency (EPA), titled "A Method for Determining Hazardous Waste Compatibility" (EPA 600/2-80-076; this manual is now out of print). In it was a compatibility matrix showing what could happen if members of 41 "Chemical Reactivity Groups" were mixed. The authors had assigned about 1,650 substances to reactivity groups. To use the chart, you identified the groups that included your substances of concern, and then, for a pair of those substances at a time, searched the chart to see what reaction could be expected if those two substances were mixed.

To develop the Chemical Reactivity Worksheet, NOAA refined this basic procedure by

• computerizing the chart;
  
• modifying and adding to the original reactivity groups to create a new set of reactive groups, and adding many more chemicals;
  
• adding information about the air and water reactivity of individual substances;
  
• adding "case history" information for many of the individual substances (shown in the Chemical Profile section of each record in the Worksheet);
  
• soliciting peer review of the new reactive groups.

Related Information

CAMEO The Computer-Aided Management of Emergency Operations (CAMEO) program is an integrated set of software modules designed to help first responders and emergency planners plan for and quickly respond to chemical accidents.