What is a PFC?

Some chemicals can form organic peroxides under ambient conditions in the presence of atmospheric oxygen or another oxidizer and an energy source, typically light or heat. These types of chemicals are called Peroxide-forming Chemicals (PFCs), where peroxide refers to an O-O bond. This O-O bond is unusually weak and can be prone to violent decomposition upon exposure to heat, mechanical shock, or friction. 

PFCs are strongly recommended to be purchased with inhibitors, which slow or prevent the formation of peroxides. Some processes or reactions require high purity, in which case, PFCs can also be purchased without inhibitors. 

A PFC Poster (PDF) is available for download, or you can request a laminated poster from EH&S. 

Learn about working with PFCs

PFC class definitions

PFCs are comprised of four classes, A-D. Each class differs in how the peroxides are formed and how reactive the materials become. The recommendations for storage, testing, and disposal differ by class. 

Class AThese PFCs can spontaneously decompose and become explosive upon exposure to air without concentration, even unopened.
Class BThese PFCs can form explosive peroxides when distilled, evaporated, or concentrated in other ways.
Class CThese PFCs are highly reactive and can autopolymerize and form extremely shock-sensitive and heat-sensitive peroxides.
Class DThese chemicals can form peroxides but cannot be clearly classified as A, B, or C.

Frequently asked questions

You can contact EH&S (ehsinfo@iastate.edu or 515-294-5359) or ISU Chemistry Stores to get the blue PFC labels for all your PFCs.

Quantofix Peroxide 100 test strips can be purchased from ISU Chemistry Stores or from major chemical vendors (e.g. Millipore Sigma, Fisher Scientific, etc.).

The WaterWorks PFC test strips available in ISU Chemistry Store are for testing water. If you want to test organic solvents and other PFCs, ensure you purchase Quantofix Peroxide 100 test strips from the ISU Chemistry Store or any other vendors.

Yes. 

  • Unexpired, open containers of Class A PFCs must be tested within 3 months of opening. 
  • Unexpired, open containers of Class B PFCs must be tested within 12 months of opening AND/OR before concentration/distillation. 
  • Unexpired, open containers of Class C PFCs must be tested within 12 months of opening. 

No, you don’t have to test new PFC containers unless they are open or expired. However, you must still attach the blue PFC label and record the day it was received, the day it should be disposed of, the PFC class, and whether it is inhibited.

Yes, unopened PFCs must be tested upon expiration. EH&S recommends disposing of expired PFCs. 

EH&S does not recommend keeping PFCs past their expiration date (nor past the recommended disposal limit for open, unexpired PFCs). If you decide to keep these PFCs, you must test them at least every 90 days. More frequent testing is recommended. 

The Principal Investigator will be accountable for all costs associated with disposal if PFCs are not submitted for disposal within the recommended time period(s). 

The rate of peroxide formation is difficult to estimate, since the O-O bond can decompose to form products that may increase or decrease the rate of peroxide formation.  In some cases, three days is enough time for peroxide to form in uninhibited materials. Even if the test results are below 100 ppm, it may reach dangerous levels of peroxides quickly. 

The Principal Investigator will be accountable for all costs associated with disposal if PFCs are not submitted for disposal within the recommended time period(s).

These PFC Disposal Guidelines (PDF) provide recommendations for how long PFCs should be stored (opened or unopened). 

Typically, no, since spray bottles and solvent wash bottles containing PFCs are frequently used, emptied, and refilled. Consider your usage rate before filling these types of containers and adjust accordingly to ensure that PFCs are not left sitting out for extended periods of time. Empty any spray or wash bottles when work is dormant. 

Class D PFCs must be tested upon expiration, then at least every 12 months. Many Class D PFCs are solids, which are difficult to test (dip-strips cannot be used). Thus, EH&S recommends disposing of expired solid PFCs. Some visual indications of peroxide formation in solid materials include color and/or texture changes.

Appendix A of the Peroxide-Forming Chemicals Guidelines (PDF) lists commonly used PFCs and their classes. 

Peroxide testing is tricky for solid chemicals, requiring more time and wet-chemistry methods (dip-strips cannot be used). Thus, EH&S recommends disposing of expired solid PFCs. Some visual indications of peroxide formation in solid materials include color and/or texture changes.

Yes, use these testing guidelines to test your PFCs based on the PFC class.

If you see any of these visual indicators, do not disturb the containers. Contact EH&S for assistance. Alert laboratory personnel and post a sign on the storage location informing everyone of potentially explosive peroxides. 

Contact EH&S and we may be able to provide you with a couple of dip strips, depending on the volume of requests. 

Specific guidance for your PFCs

Contact the EH&S Lab Safety team if you have questions about your PFCs.