Analyze an SDS

DOT Division 5.2: Organic Peroxides

Division 5.2 is the DOT division for organic peroxides: organic compounds containing the bivalent -O-O- structure that can be considered derivatives of hydrogen peroxide. They are thermally unstable and may undergo self-accelerating decomposition, burn quickly or be sensitive to impact or friction.

How it is defined

  • Organic peroxides are assigned types (from A, the most hazardous, to G) based on how they behave in tests, and each has a control temperature in some cases.
  • Many organic peroxides must be shipped and stored temperature-controlled.
  • Typical uses include initiators for plastics polymerization and hardeners for resins.

Summary of 49 CFR Parts 171 to 180. The regulations and the Hazardous Materials Table (49 CFR 172.101) control any shipment.

Label and placard

Colors
Upper half red, lower half yellow
Symbol
Flame over a circle

A diamond with a red top and yellow bottom, a flame over a circle and the number 5.2.

Packing groups

No packing groups. Organic peroxides are identified by type and temperature control requirements. How packing groups work.

Common examples

  • Benzoyl peroxide
  • Methyl ethyl ketone peroxide (MEKP)
  • Dicumyl peroxide

How it relates to GHS

GHS groups organic peroxides with self-reactive substances, using the same type A to G scheme.

DOT classes and GHS classes are assigned under different rules, so a product can have different severity labels in each. See also all GHS hazard classes.

Safe handling reminders

  • Keep below the control temperature on the label.
  • Keep away from accelerators, reducing agents and heavy metals.
  • Never mix peroxide hardener with accelerator directly.

Where to find it on an SDS

Section 14 shows Division 5.2, UN number, any temperature control requirement and the ERG guide number. Look in Section 14: Transport information. Hazard classification for the workplace is in Section 2. You can also see how a UN number points to a response guide on the UN and NA numbers page.

Frequently asked questions

What is Division 5.2?

Division 5.2 is the DOT division for organic peroxides, thermally unstable compounds that can burn, decompose violently or be sensitive to impact or friction.

General reference only. It does not replace the supplier's SDS or the current federal regulations.