Peroxide forming chemicals, or PFCs, are materials that can react with oxygen over time to form unstable organic peroxides. These peroxides may become sensitive to heat, friction, shock, or concentration, creating a serious fire and explosion hazard. Proper labeling is one of the most important steps laboratories can take to identify PFC hazards, track container age, document testing, and ensure timely disposal.

All peroxide forming chemicals must be clearly labeled and managed from the time they are received until they are used, tested, or disposed.

When PFC Labels Are Required

A Peroxide Forming Chemical label is required for any new or existing chemical that is known or suspected to form peroxides. Labels should be applied as soon as the material is received, opened, transferred, or identified in the laboratory. Because peroxide formation is time-dependent, laboratories should not wait until a material is ready for testing or disposal before applying the label.

PFC labels are required when:

• A new peroxide forming chemical is received by the laboratory.
• An existing peroxide forming chemical is identified during inventory review, inspection, or laboratory cleanup.

Each PFC label should be completed with the following information:

Date Received
Enter the date the container was received by the laboratory. This date is used to track unopened shelf life and determine when disposal may be required.

Date Opened
Enter the date the container was first opened. This date is used to determine when peroxide testing should begin and when the container may need to be disposed.

Discard No Later Than Date
Enter the date by which the material must be used, tested, or submitted for disposal based on the PFC class, inhibitor status, manufacturer expiration date, or laboratory-specific hazard assessment.

PFC Class
Circle or mark the appropriate peroxide forming chemical class: A, B, C, or D. The PFC class helps determine storage, testing, and disposal expectations.  Visit the PFC Chemical List webpage for additional PFC class information and examples.

Inhibited Status
Mark whether the material is inhibited or uninhibited. Inhibited materials contain stabilizers that slow peroxide formation. Uninhibited materials may form peroxides more rapidly and require closer management.

Peroxide Test Log
Use the test log to document each peroxide test, including the test date, ppm result, and initials of the person performing the test. Visit the Testing Peroxide Forming Chemicals webpage for testing information.

Ordering PFC Labels

Environmental Health & Safety provides Peroxide Forming Chemical labels. Labels may be requested through the EHS Assistance Database using the Supply Request link and should be kept available in areas where peroxide forming chemicals are received, stored, or used.

You can also contact EHS to request supplies by emailing hazmat@missouri.edu or calling (573) 882-7018.