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UN identification number

UN3545: Articles containing organic peroxide

As listed: Articles containing organic peroxide, n.o.s.

UN3545 appears 1 time in the Hazardous Materials Table (49 CFR §172.101). Hazard class 5.2.

ID numberUN3545
Hazard class5.2
Packing groupnot assigned
Label codes5.2

All §172.101 entries for UN3545

Proper shipping nameClassPGLabels
Articles containing organic peroxide, n.o.s.5.2—5.2

Open any entry for packaging sections, special provisions, air limits and vessel stowage.

What it means

5.2
Class 5.2 — Organic peroxide. Organic compounds containing an oxygen-oxygen bond; they can be unstable and burn intensely.

Label codes (column 6): 5.2 → Organic peroxide label.

UN numbers are recognized for international and domestic transport.

Example basic description

UN3545, Articles containing organic peroxide, n.o.s., 5.2

Proper shipping name shown without the table's italic descriptive text. Order per §172.202: ID number, proper shipping name, hazard class, packing group. Example only — add technical names, “RQ”, quantities and other elements your shipment requires.

What to check next

  1. Match the name. Compare your SDS Section 14 to the proper shipping names above and pick the row with your packing group.
  2. Read the special provisions on the entry page (§172.102) — they can add limits or exceptions.
  3. Check packaging — the entry page lists the Part 173 sections for exceptions, non-bulk and bulk.
  4. Labels & placards. Placarding depends on class and quantity — see Table 1 vs Table 2.
  5. Emergency response. Find the response guide for UN3545 in the current PHMSA Emergency Response Guidebook.
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Common questions about UN3545

What is UN3545?

UN3545 is the identification number for Articles containing organic peroxide, n.o.s. in the DOT Hazardous Materials Table (49 CFR §172.101).

What hazard class is UN3545?

UN3545 is listed under hazard class 5.2 (organic peroxide).

What packing group is UN3545?

Packing group for UN3545: not assigned. Where several rows exist, the packing group that fits your material decides which row applies.

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Source: Hazardous Materials Table (49 CFR §172.101), eCFR.gov — current as of Oct 23, 2026. View the official table. Reference only — verify current requirements before shipping.